Phenomenology 2026 Symposium

11 May 2026, 08:00 → 13 May 2026, 14:00 US/Eastern

University of Pittsburgh

*** Please be aware of scams! Our attention has been drawn to a Phishing email from"...Conference-booking.com", that asks you to complete a form including your credit card information. Please be aware that we will never ask for any credit card or other payment information from you outside of the registration from this website.  Please email us at pittpacc@pitt.edu if you have any questions and concerns. ***

The 2026 Phenomenology Symposium (PHENO) will be held May 11 - 13, 2026 at the University of Pittsburgh.  It will cover the latest topics in particle phenomenology and theory as well as related issues in astrophysics and cosmology.  We would like to encourage you to register and submit an abstract for a parallel talk.  All talks are expected to be in person. We hope to see you in May!

Deadlines: 

• Student travel award application deadline: April 13, 2026
• Early registration deadline (discount reg fee): April 17, 2026
• Dorm sign-up deadline: April 15, 2026
• Parallel talk submission deadline: April 24, 2026
• Registration closes: May 1, 2026

Topics to be Covered:

• Dark Matter Theory and Detection
• Electroweak, Higgs, and Top Quark Physics
• Neutrino Physics
• Quark and Lepton Flavor Physics
• New Physics at Future Colliders
• Particle Cosmology
• Astro-Particle Physics
• New Developments in Theory
• Gravitational Waves and Particle Physics
• Machine Learning and Artificial Intelligence in Particle Physics 
• Computing, Analysis Tools, and Data Handling

Plenary Program Speakers: 

• Prateek Agrawal (UCSB):Strong CP Problem and the Physics with Axions
• Jonathan Blake (Northeastern University): Probing the Dark Energy
• Federico Buccioni (CERN): Precision Physics in the LHC Era 
• Marcela Carena (Perimeter Institute/U Chicago): Pathways to Discoveries in Particle Physics
• Regina Demina (Rochester U./CMS): Highlights of the Recent LHC Results
• Colin Hill (Columbia U): CMB Power Spectrum and New Physics from ACT-DR6
• Matheus Hostert (U. Iowa): Neutrino Physics Phenomenology
• Gordan Krnjaic (FNAL): Primordial Black Holes and Particle Physics 
• Zoltan Ligeti (LBNL): Flavor Physics in the New Era
• Hugh Lippincott (UCSB/LZ): Progress and Prospects in Dark Matter Direct Detection
• Zhen Liu (U. of Minnesota): New Directions in Collider Physics 
• Fabio Maltoni (Bologna/UC Louvain): Quantum Information Meets Collider Physics
• Konstantin Matchev (U. Alabama): AI & ML for Particle Physics 
• Matt Reece (Harvard): New Developments in Particle Theory
• Nicholas Rodd (LBNL): Dark Matter Indirect Searches and Astroparticle Physics 
• Sarah Demers (Yale U./ATLAS): HL-LHC and Future Perspectives
• Yuhsin Tsai (Notre Dame): Particle Physics at the Cosmic Frontier 
• Mark Ross-Lonergan (Columbia U.): Highlights of Neutrino Physics 

Mini Reviews: 

• Sergei Gleyzer: (U. of Alabama): Deep Learning in HEP

Special Events: 

• Conference Welcome Reception: Sunday, May 10, 6:30 PM.
• Early Career Forum: Monday, May 11, 1:00 - 2:00 PM. Presenter: Gil Paz (Wayne State University)
  
• Conference Banquet: Tuesday, May 12, 7:00 - 9:30 PM.

Student Travel Awards:

With support from the NSF and DOE, there are a number of awards (up to $300 each) available to domestic graduate students for travel and accommodation to Pheno 26. A student applicant should send an updated CV and a statement of financial need, indication of the talk submission to Pheno 26, and arrange for a short recommendation letter sent from their thesis advisor, by email to pittpacc@pitt.edu with the subject line "Pheno 26 travel assistance". The decision will be based on the academic qualification and the financial need. The deadline for the application is April 13, and the winners will be notified by April 17.  (Each research group may be limited to one awardee. Winners in the previous years may have lower priority for consideration. Winner institutes and names will be announced at the Symposium banquet on Tuesday, May 12.)

"Conversation Desks":

To further facilitate conversations among the participants, we will set up a few desks hosted by experienced physicists at the conference welcome reception, Sunday evening. They are:

Sekhar Chivukula (UCSD), Hooman Davoudiasl (BNL), Elizabeth Simmons (UCSD), Lian-Tao Wang (U. of Chicago) 

Conference Venue 

All Plenary / Parallel Sessions: University of Pittsburgh David Lawrence Hall
3942 Forbes Ave.  Pittsburgh, PA 215260

Career Forum: William Pitt Union, Ballroom
3959 Fifth Ave. Pittsburgh, PA 15260
Across the street from David Lawrence Hall

Sunday Welcome Reception: William Pitt Union, Lower Lounge
3959 Fifth Ave. Pittsburgh, PA 15260

 

Dinner Banquet: University Alumni Hall, Connolly Ballroom
4227 Fifth Ave. Pittsburgh, PA 15260

 

PHENO 2026 Local Organization Committee: 

Brian Batell, Kun Cheng, Christopher Condon (Technical Support), Arnab Dasgupta, Ayres Freitas, Joni George (Contact), Gracie Gollinger (Technical Support), Tao Han (chair), Sam Homiller, Adam Leibovich, Zahra Tabrizi

PHENO 2026 Program Advisors:

Vernon Barger, Lisa Everett, JoAnne Hewett, Tae Min Hong, Arthur Kosowsky, James Mueller, Vittorio Paolone, Tilman Plehn, Laura Reina, Vladimir Savinov, Lian-Tao Wang, Andrew Zentner. 

Past PHENOs:

PHENO 2025

Monday 11 May

08:00 → 08:40 Registration and Breakfast

08:40 → 10:30 Plenary: Monday Early

Convener: Elizabeth Simmons (University of California, San Diego)

08:40 Welcome

Speaker: Andrew Zentner (University of Pittsburgh)

08:45 Progress and Prospects in Dark Matter Direct Detection

Speaker: Hugh Lippincott (UCSB)

09:20 Dark Matter Indirect Searches and Astroparticle Physics

Speaker: Nicholas Rodd

09:55 CMB Power Spectrum and New Physics from ACT-DR6

Speaker: Colin Hill (Columbia University)

10:30 → 11:00 Coffee Break

11:00 → 12:45 Plenary: Monday Late

Convener: Shufang Su (University of Arizona)

11:00 Probing the Dark Energy

Speaker: Jonathan Blazek

11:35 Particle physics at Cosmic Frontier

Speaker: Yuhsin Tsai (University of Notre Dame)

12:10 Primordial Black Holes and Particle Physics

Speaker: Gordan Krnjaic (Fermilab)

12:45 → 14:15 Lunch Break

13:00 → 14:00 Forum on early career development

Convener: Gil Paz

13:00 Forum on early career development

Speaker: Gil Paz

14:15 → 16:00 Cosmology: Neutrino, BBN, DM

14:15 New prediction for the primordial deuterium abundance with Gaussian processes

The exact abundances of light elements produced during Big Bang Nucleosynthesis (BBN) are highly sensitive to the physics of the primordial plasma. Percent-level measurements of primordial deuterium have enabled precision cosmology from BBN; to match this level of precision in theoretical calculations, a careful estimate of uncertainties arising from nuclear reaction cross sections is of paramount importance. We present a novel method to incorporate measured nuclear cross section data directly into BBN calculations using Gaussian processes. With Gaussian processes, we generate a probability distribution over a broad class of functions consistent with the data without needing to choose a specific functional form for the fit, while fully accounting for both statistical and systematic uncertainties. We pass draws from the Gaussian process into the BBN code, propagating experimental uncertainties to robust predictions of primordial element abundances. We demonstrate the reliability of our method by generating realistic mock cross section datasets and consistently recovering the expected results within predicted uncertainties. Assuming the Planck value for the baryonic density of the universe ωb for our calculation of the primordial deuterium abundance, we find potentially important implications for the concordance between CMB and BBN within the ΛCDM model.

Speaker: Timothy Launders (Boston University)

14:30 To $\nu$ or Not to $\nu$: That is the Interaction

In this talk, I will discuss a novel way of modeling neutrino self-interactions for cosmological observables. In this model, active neutrinos resonantly convert to self-interacting dark radiation after BBN but before the CMB epoch. It yields cosmological signatures equivalent to those of self-interacting neutrinos and naturally accommodates relaxed neutrino mass constraints. Our analysis shows that Planck + DESI data prefer strongly interacting DR to CDM, while remaining consistent with all other laboratory and BBN constraints.

Speaker: Dr Subhajit Ghosh (The University of Texas at Austin)

14:45 Superradiant interactions of cosmic relics and how to look for them

In this talk I will do three things. First, I will outline the conditions under which the interaction rate of inelastic processes with a system consisting of N targets scales as N^2. Second, I will present computations of interaction rates for several weakly interacting particles, including the cosmic neutrino background and axion dark matter, and will explain the underlying physics. Third, I will present a concrete experimental protocol using Nuclear Magnetic Resonance that can extract these effects through quantum observables not relying only on net energy transfer. This protocol has the potential to significantly accelerate axion and dark photon dark matter searches and extend the reach of existing axion experiments to probe QCD axion-nuclear spin couplings. More broadly, it paves the way for detecting coherent inelastic interactions from other cosmic relics---most notably the cosmic neutrino background---and establishes nuclear-spin-based systems as a new class of quantum, ultra-low-threshold detectors.

Speaker: Marios Galanis (Stanford University)

15:00 A win-win Coupling, Alleviating the Hubble Tension in the Neutrino Early Dark Energy Interacting Models

This study explores a "win-win" coupling between a scalar field and the cosmic neutrino background to address the Hubble tension and the cosmic coincidence problem. We propose a model featuring a scalar bosonic field with a scale-free, quartic scalar potential $U(\phi) = \lambda \phi^4$ that interacts with neutrinos to generate an effective potential with temperature-dependent degenerate minima. At high temperatures in the early universe, the field is trapped in a frozen minimum where effective neutrino masses vanish. As the cosmic neutrino background cools, the field adiabatically tracks the evolving minimum toward the origin, allowing the neutrino mass to reach its bare value of approximately 0.1 eV at late times. Numerical integration demonstrates that this mechanism produces a subdominant early dark energy component peaking at approximately 10% of the total energy density near matter-radiation equality at a redshift of approximately 3400. This localized energy injection reduces the sound horizon, alleviating the Hubble tension while remaining consistent with Big Bang Nucleosynthesis and Cosmic Microwave Background constraints. The subsequent rapid decay of the early dark energy component ensures the model's convergence to the standard Lambda Cold Dark Matter framework at low redshifts.

Speaker: Dylan McCauley (Carnegie Mellon University)

15:15 The cosmological evolution of coupled neutrino-ultralight dark matter

The high densities in the early Universe provide a unique laboratory to constrain couplings between feebly interacting particles, such as dark matter and neutrinos. I will introduce a model where neutrinos get their mass from a small diagonal coupling to ultralight dark matter (ULDM), and how to consistently use cosmology, namely Big Bang Nucleosynthesis (BBN), to constrain it. In particular, I will emphasize the need for accounting for the neutrino backreaction in the ULDM evolution, which causes its energy density to scale as radiation when the neutrino interaction dominates the dynamics. Finally, I will discuss the effect of the coupled neutrino-ULDM fluid in BBN and how to use primordial element abundances to obtain competitive constraints.

Speaker: Antoni Bertolez-Martinez (University of Wisconsin-Madison)

15:30 Efficiency of primordial black hole evaporation into dark matter

Primordial black holes can act as non-thermal sources of dark matter through Hawking evaporation, but the viable parameter space depends sensitively on greybody factors, massive-particle thresholds, and the full particle content of the dark sector. In this talk, I will examine the efficiency of the process by which a black hole dumps its mass into the creation of a population of dark matter particles. Using minimal supersymmetry as a test case, I will present improved semi-analytic calculations of PBH emission rates, validated against a modified version of BlackHawk that incorporates realistic supersymmetric spectra rather than a single dark matter degree of freedom. I will show that including the full heavy SUSY sector, especially the scalar-rich part of the spectrum, and the cascade decays into the lightest supersymmetric particle significantly enlarges the allowed PBH–dark matter parameter space and lowers the PBH abundance required to explain the observed relic density.

Speaker: Brian Zhang

15:45 Primordial Neutron Stars

I will describe a novel cosmological scenario in which baryonic neutron stars could plausibly form in the early universe. If baryogenesis initially produces an excessively-large baryon asymmetry, the baryonic mass inside the horizon can exceed the minimum neutron star mass before big bang nucleosynthesis (BBN). While this large asymmetry is present, non-relativistic baryons can dominate the universe and enhanced density perturbations on small scales can gravitationally collapse Hubble patches shortly after horizon re-entry. For some initial perturbations, just below the threshold for black hole formation, this collapse will be arrested only by nuclear pressure, possibly resulting in neutron star formation. Afterwards, there must be a large entropy injection to restore the observed baryon asymmetry and preserve the successful predictions of standard BBN. Unlike neutron stars that form from stellar collapse, primordial neutron stars can, in principle, be as light as 0.1 solar masses, limited only by the nuclear equation of state.

Speaker: Duncan Rocha (University of Chicago)

14:15 → 16:00 Dark Matter: DM at Colliders

14:15 Searches for BSM physics using challenging and long-lived signatures with the ATLAS detector

Various theories beyond the Standard Model predict new, long-lived particles with unique signatures which are difficult to reconstruct and for which estimating the background rates is also a challenge. Signatures from displaced and/or delayed decays anywhere from the inner detector to the muon spectrometer, as well as those of new particles with fractional or multiple values of the charge of the electron or high mass stable charged particles are all examples of experimentally demanding signatures. The talk will focus on the most recent results using 13 and 13.6 TeV pp collision data collected by the ATLAS detector.

Speaker: Michael Revering (University of Cambridge (GB))

14:30 Leptonically rich confining dark sectors from dark hadronization: recasting an ATLAS four-lepton analysis

Hidden valley / dark sector models can produce multilepton signals with low backgrounds, especially when vectors decay promptly to charged leptons, a signature which remains relatively unexplored. In this talk, I extend our recent recast of an ATLAS four-lepton search to models in which a scalar mediator $S$, singly produced at the LHC, decays to dark gluons, which in turn produce a shower of dark mesons. Dark vector mesons $\rho_D$ can yield same flavor opposite charge dilepton pairs, while dark pions $\pi_D$ remain invisible. I discuss benchmark models with a two-flavor QCD-like dark sector, the treatment of trigger and reconstruction effects in the recast, and the dominant theoretical uncertainties associated with dark showering and hadronization.

Speaker: Junyi Cheng (Harvard University)

14:45 Recent highlights of dark matter searches from CMS

Determination of the nature of dark matter is one of the most fundamental problems of particle physics and cosmology. This talk presents recent searches for dark matter particles from the CMS experiment at the Large Hadron Collider.

Speaker: Murtaza Safdari (Fermi National Accelerator Lab. (US))

15:00 CMS Run-2 search for a boosted dark Higgs boson decaying into a bottom quark-antiquark pair

In this talk, I will be talking about the CMS Run-2 search for dark matter produced in association with a dark Higgs boson decaying into a bottom quark-antiquark pair. The search is performed with proton-proton collision data at a center-of-mass energy of 13 TeV, taken during the 2016-2018 data-taking period, and corresponds to an integrated luminosity of 138 fb^{-1}. The results are interpreted in terms of a theoretical model that predicts the existence of a Higgs-boson-like particle in the dark sector (i.e. a dark Higgs boson), together with a spin-1 gauge boson mediator. The experimental signature consists of a large missing transverse momentum from dark matter production and a resonant structure in the invariant mass of the bottom quark-antiquark pair from the dark Higgs boson decay. Upper limits at 95% confidence level on the signal strength for dark Higgs boson mass hypotheses below 160 GeV are set. Values of the mediator mass up to 4.5 (2.5) TeV are excluded for a dark Higgs boson mass of 50 (150) GeV, which represents the most stringent limits set to date.

Speaker: Erdem Yigit Ertorer (Carnegie-Mellon University (US))

15:15 Probing Freeze-In Dark Matter via a Spin-2 Portal at the LHC with Vector Boson Fusion and Machine Learning

The persistent absence of signals in traditional dark matter searches has intensified interest in scenarios beyond the canonical weakly interacting massive particle paradigm. In this work, we investigate the collider phenomenology of feebly interacting dark matter produced via the freeze-in mechanism through a spin-2 portal. We consider a framework in which a massive graviton-like mediator couples minimally and universally to the energy--momentum tensor of both the Standard Model (SM) and the dark sector. Such interactions arise naturally in extra-dimensional constructions and effective theories of gravity, providing a theoretically well-motivated and predictive setup. We systematically connect early-Universe cosmology with collider observables by identifying regions of parameter space consistent with freeze-in conditions and the observed dark matter relic abundance, and examining their testability at the Large Hadron Collider (LHC). Focusing on bosonic fusion production channels, which are particularly sensitive to spin-2 interactions, we analyze invisible mediator decay signatures and assess current and projected experimental sensitivities. To enhance sensitivity in this challenging regime of feeble couplings, we develop a search strategy based on machine-learning algorithms. Our results demonstrate that collider searches can probe substantial regions of the cosmologically viable freeze-in parameter space, highlighting the high-luminosity LHC as a powerful laboratory for feebly interacting dark sectors. This study establishes a concrete and complementary pathway to test freeze-in dark matter scenarios through spin-2 portals, thereby bridging gravitationally motivated new physics, cosmology, and high-energy collider experiments.

Speaker: Junzhe Liu

15:30 Boosting Dark Matter with the LHC Beam: A New Forward Signature

We propose a new method for discovering dark matter through the scattering of LHC protons off ambient dark matter. Over-dense populations of dark matter may accumulate near the Earth’s surface, for example in scenarios with strongly interacting dark matter. Protons circulating in the beam traverse this over-density and scatter dark matter particles forward along the beam direction, generating a flux of boosted dark matter toward forward detectors such as FASER, where it can rescatter and produce an observable signal. We show that this mechanism yields a striking signal, providing a novel collider signature of dark matter.

Speaker: Andrew Evans (University of California Irvine)

15:45 Search for Sub-GeV Axion-Like Particles at EBES Pilot Run

Dark matter is believed to constitute approximately 25% of the total energy density of the Universe, as inferred from observations such as galactic rotation curves and the cosmic microwave background, yet it has not been directly detected. Axion-like particles (ALPs), predicted in various extensions of the Standard Model, are well-motivated dark matter candidates in the MeV–GeV mass range. EBES (Electron Beam-dump Experiment at KEK LINAC Switching Yard 3) is a new beam-dump experiment designed to search for ALPs using 4 GeV positron or 7 GeV electron beams produced at the KEK LINAC. ALPs produced through interactions of electrons or positrons with a tungsten target are detected via their decay into two photons using downstream lead-glass calorimeters. A pilot run conducted in December 2023 with a 4 GeV positron beam collected data corresponding to 1.3×10^14 positrons on target. This talk will present the results of the analysis of these data, demonstrating that EBES has sensitivity to ALPs in a parameter space complementary to other experiments.

Speaker: Tomoya Iizawa (University of Tokyo (JP))

14:15 → 16:00 Electroweak: Higgs, top

14:15 ATLAS results on top quark mass and properties

The top-quark mass is one of the key fundamental parameters of the Standard Model that must be determined experimentally. Its value has an important effect on many precision measurements and tests of the Standard Model. In this contribution, the top quark mass measurements by the ATLAS experiment are reviewed. These include measurements in two broad categories, the direct measurements, where the mass is determined from a comparison with Monte Carlo templates, and determinations that compare differential cross-section measurements to first-principle calculations. In addition, new ATLAS results on top-quark properties are shown.

Speaker: Frederic Derue (LPNHE-Paris CNRS/IN2P3)

14:30 ATLAS results on associated top quark production (Top+X)

The high center-of-mass energy of proton-proton collisions and the large available datasets at the CERN Large Hadron Collider allow the study of rare processes of the Standard Model with unprecedented precision. Measurements of rare SM processes provide new tests of the SM predictions with the potential to unveil discrepancies with the SM predictions or provide important input for the improvement of theoretical calculations. In this contribution, total and differential measurements of associated top-quark production are shown using data taken with the ATLAS Experiment at a center-of-mass-energy of 13 TeV. These measurements provide important bounds on the electroweak couplings of the top quark, often with Effective Field Theory interpretations and constrain backgrounds that are important in searches for Higgs production and for new phenomena beyond the SM.

Speaker: Lining Mao (Shanghai Jiao Tong University (CN))

14:45 Higgs properties (mass, width, CP) and EFT measurements from ATLAS

This talk presents precise measurement of the properties of the Higgs boson, including its mass, total width, spin and CP quantum number. The measurements are performed in various Higgs boson production and decay modes, as well as their combinations. Interpretation in the context of Effective Field Theory (EFT) frameworks and specific BSM models are also shown.

Speaker: Alex Zeng Wang (University of California,Santa Cruz (US))

15:00 Higgs boson production and decay rate measurements with the ATLAS experiment

With the full Run 2 pp collision dataset collected at 13 TeV, very precise measurements of Higgs boson production and decay rates can be performed, shedding light over the electroweak symmetry breaking mechanism. This talk presents these precise measurements including total and fiducial cross-sections for the main Higgs boson processes as well as branching ratios into final states with bosons and fermions. Differential cross-sections in a variety of observables are also reported, as well as a fine-grained description of the Higgs boson production kinematics within the Simplified Template Cross-section (STXS) framework. Combinations of such measurements are also presented.

Speaker: Mira Varma (Yale University (US))

15:15 HH, HHH searches, Higgs potential at the LHC

In the Standard Model, the ground state of the Higgs field is not found at zero but instead corresponds to one of the degenerate solutions minimising the Higgs potential. In turn, this spontaneous electroweak symmetry breaking provides a mechanism for the mass generation of nearly all fundamental particles. Experimentally, the Higgs boson self-coupling and thereby the shape of the Higgs potential, can be probed through the production of Higgs boson pairs (HH). In this talk, the latest HH searches by the ATLAS experiment using the LHC Run 2 and Run 3 datasets are reported. Non-resonant HH search results are interpreted both in terms of sensitivity to the Standard Model and as limits on the Higgs boson self-coupling and the quartic VVHH coupling. Additionally, extrapolations of recent HH and HHH results towards the High Luminosity LHC upgrade are also discussed.

Speaker: Romano Orlandini (Universita e INFN Roma Tre (IT))

15:30 Beyond the Standard Model in the Higgs sector at ATLAS

The discovery of the Higgs boson with the mass of about 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable of explaining some observations by itself. Many extensions of the Standard Model addressing such shortcomings introduce additional Higgs bosons or beyond-the-Standard-Model couplings to the Higgs boson. In this talk, the latest searches for BSM Higgs decays are reported.

Speaker: Kevin Sedlaczek (Northern Illinois University (US))

15:45 Searches for rare decays of the Higgs boson into light pseudoscalars in the CMS experiment.

A variety of searches for the SM Higgs boson decaying to a pair of light pseudoscalars are performed with pp collisions data collected by the CMS detector. In this talk, we present recent highlights from these searches.

Speaker: Sweta Baradia (Saha Institute of Nuclear Physics (IN))

14:15 → 16:00 Flavor Physics: BSM

14:15 Flavor physics at the EIC with b-jet tagging

We define an approximate conserved quantum number ("b-Parity") of the
SM: $b_P = (−1)^n$, where $n$ is the number of produced b-jets in scattering processes with no $b$-quarks in the initil state. We then apply the concept of b-Parity in the reaction $e + p/A \to n \cdot j_b + X$, to explore new TeV-scale flavor-changing interactions involving the 3rd generation quarks at the EIC; simply by counting the number of b-jets in the final state. In particular, the SM single and di-jet production at the EIC which occur through the charge current interactions, $e + p/A \to j + {\rm MET}$ and $e + p/A \to 2 · j + {\rm MET}$ , are $b_P$-even since the $b_P$-violating (i.e, $b_P = −1$) SM signals for these processes are necessarily CKM suppressed and, therefore, have a vanishingly small production rate. In contrast, we show that new flavor physics can generate $b_P = −1$ signals at the EIC whose only significant SM background is due to b-jet misidentification. Thus, b-Parity can be used as a simple and sensitive probe of new flavor violating physics at the EIC, reaching a sensitivity to scales of new physics which is remarkably more than 30 times larger than the EIC CM energy. This critically depends on the b-tagging efficiency and purity as well as the feasibility of electron-beam polarization.

Speaker: Shaouly Bar-Shalom (Technion, Israel)

14:30 Hunting for New Physics with Tau Decays

Baryon number violation (BNV) provides one of the most sensitive probes of physics beyond the Standard Model. In this work, we investigate rare BNV tau decays induced by effective field theory (EFT) operators, including scenarios with associated dark-sector final states. We demonstrate that any framework generating BNV tau decays necessarily induces proton decay, leading to stringent constraints from existing experimental bounds on proton lifetime. As a result, we find that the branching ratios ($\mathcal{B}$) for $\tau$ decays even after involving dark-sector particles are highly suppressed, of order $\mathcal{O}(10^{-30})$, rendering their direct observation extremely challenging at current facilities such as Belle II. We further explore proton–tau mixing operators and analyze the resulting multi-body proton decay channels mediated by semi-leptonic tau decays. The obtained spectra of the final state charged pions from those processes indicate that one can still search for them in Super-K/ Hyper-K.

Speaker: Sohini Pal (University of Cincinnati, OH, USA)

14:45 Light ALPs and Lepton Flavor Violation in Muonic Atoms

The nuclei-assisted transition $\mu^- e^- \to e^- e^-$ in a muonic atom is a striking charged-lepton flavor-violating process that muon-conversion experiments such as Mu2e and COMET will probe. We analyze this process in a simplified axion-like particle (ALP) model with couplings to light charged leptons and, possibly, to a dark sector, and compute the transition rate. The rate scales with the cube of the effective nuclear charge, and in contrast to heavy-mediator scenarios, light ALPs can parametrically enhance the branching ratio by lifting the propagator suppression. We confront the model with a broad set of low-energy, astrophysical, and beam-dump constraints on ALP-lepton interactions, and find that the maximal branching ratio in aluminum is $\sim \mathcal{O}(10^{-20})$, with even stronger suppression in the resonant ALP-mass region. Remarkably, the surviving parameter space lies close to the current $\mu \to 3e$ limit, implying that the upcoming Mu3e experiment will probe the most phenomenologically relevant region.

Speaker: Dr Girish Kumar (University of South Carolina)

15:00 Matter Unification and Lepton Flavor Violation

We explore the idea of quark–lepton unification at low energies. In particular, we discuss the minimal framework for matter unification at the multi-TeV scale, in which neutrino masses are necessarily generated via the inverse seesaw mechanism. To assess the testability of this theory for physics beyond the Standard Model, we analyze current experimental constraints and derive the corresponding lower bound on the symmetry-breaking scale. We reexamine the impact of existing limits from lepton number violating meson decays, taking into account the freedom associated with unknown quark–lepton mixing angles. Furthermore, we study the correlation between bounds from meson decays and $\mu \to e$ conversion. We demonstrate that the upcoming $\mu \to e$ conversion experiment at Fermilab can play a crucial role in probing quark–lepton unification at the multi-TeV scale.

Speaker: Hridoy Debnath

15:15 Exploring Right-Handed Neutrinos as Probes of New Physics in Semileptonic $\bar{B}$ Decays

Recent measurements of the ratios of branching ratios $R(D) \equiv \frac{\mathcal{B}(\bar{B} \to D \tau^- \bar{\nu}_{\tau})}{\mathcal{B}(\bar{B} \to D \ell^- \bar{\nu}_{\ell})} $ and
$R(D*) \equiv \frac{\mathcal{B}(\bar{B} \to D^* \tau^- \bar{\nu}_{\tau})}{\mathcal{B}(\bar{B} \to D^* \ell^- \bar{\nu}_{\ell})} $ by the Belle, BaBar and LHCb experiments indicate evidence for New Physics(NP) surpassing the predictions of the Standard Model (SM), with the deviation reaching a combined significance of $3.8\sigma$. In this work, we investigate the differential decay distributions of $ \bar{B} \to D^* \ell \bar{N}$, where ( N ) is a heavy right-handed neutrino and $\ell= e, \mu$. We employ a newly developed Monte Carlo event generator built upon the EvtGen framework, used specifically to simulate beyond-the-standard model processes. We validate the implementation of the model by comparing the Monte-Carlo results with analytical results for various observables in the angular distribution such as $A_{FB}$, $S_{3}$, $S_{5}$ etc.

Speaker: Kumar Pandey (University of Mississippi)

15:30 Searches for Exotic Heavy Resonances with the ATLAS detector

Many extensions of the Standard Model predict new heavy particles that could appear as resonances decaying into quarks, leptons or photons. Using 13 and 13.6 TeV pp collision data from the LHC, ATLAS explores these signatures, including boosted regimes where high-momentum final states pose unique reconstruction and background estimation challenges. This talk presents recent results and their implications for new physics at the TeV scale.

Speaker: Saad Mohiuddin (Oklahoma State University (US))

15:45 Quantum Tomography of Neutral Mesons in Flavor Space

The flavor space of particles produced in collider environments contains informative quantum correlations. We present a systematic approach for constructing the complete flavor density matrix for a meson and antimeson system (MM¯ ) in the Bloch vector space at a given time t. We show that the quantum states of B_s^0 and K^0 systems can be efficiently reconstructed to high precision, which not only makes all quantum information measurements available in the flavor sector, but also facilitate the study of production mechanisms, decoherence phenomena, and potential new sources of CP violation.

Speaker: Arthur Wu

14:15 → 16:00 New Developments in BSM Searches

14:15 Improved supernova bounds on CP-even scalars: cooling and decay constraints

Supernovae provide among the most powerful probes of weakly-coupled new particles in the MeV mass range, where laboratory experiments lose sensitivity. In this work, we constrain the mixing angle $\sin \theta$ of a Higgs mixed scalar to five orders of magnitude below the existing collider bounds ($\sin \theta \sim 10^{-9}$) using an improved supernovae cooling bound and with new decay-based constraints from the galactic 511 keV positron flux and energy deposition in low-energy Type II-P supernovae. We also extend our analysis to a hadrophilic scalar model, constraining Yukawa couplings down to $y_N \sim 10^{-10}$.

Speaker: Anirudhan Alanthatta Madathil (University of Utah)

14:30 Higher Axions

A large fraction of the experimental efforts searching for the (QCD) axion focus on smaller-scale, time-intensive, resonant searches. These searches would greatly benefit from a precise estimate of the axion mass. In theory, the axion mass can be inferred from the observed dark matter abundance and numerical simulations point towards an axion mass (slightly) higher than currently searched for. These numerical predictions require axion models to have both high quality and a predictive cosmological history - that is - a post-inflationary scenario.

In this talk, I want to introduce the minimal requirements to obtain axions with exponentially good quality and a predictive cosmological scenario. These ingredients appear in theories where an axion coming from a higher-form gauge field mixes with the phase of a complex scalar field. We present a simple toy model on a 5-dimensional manifold with boundary. If time permits, we show how these scenarios may arise in string theory compactifications and discuss how to overcome additional complications these specific UV completions introduce.

Speaker: Arthur Platschorre (Cornell University)

14:45 Composite Quarks and Leptons: Flavor Signatures of a Preon Theory

We discuss a renormalizable composite SU(15) model in which the Standard Model quarks, leptons, and the Higgs arise as bound states of an underlying confining chiral gauge theory. Symmetries and large-(N) power counting naturally suppress baryon-number violation, allowing compositeness scales as low as (10^{4},TeV) while remaining consistent with proton-decay bounds. We focus on the flavor structure of the model, where the same Yukawa couplings that generate the observed fermion masses and quark mixing also induce a broad class of flavor- and precision-sensitive effects. This makes low-energy observables a powerful and complementary probe of compositeness, in some cases reaching beyond the usual proton-decay benchmark.

Speaker: Amartya Sengupta (The University at Buffalo, SUNY, USA)

15:00 Large-Width New Physics at Colliders: A Gauge-Invariant Resummation Approach

Broad resonances challenge the standard Monte-Carlo treatment of unstable particles, which introduces a Breit–Wigner width into leading-order matrix elements and can generate unphysical gauge artifacts. We develop a gauge-consistent framework that combines a Dyson-resummed propagator with Slavnov–Taylor-identity–implied resummed vertices, enabling a consistent implementation in MadGraph5. In the Type-I seesaw model, heavy Majorana neutrinos naturally satisfy $\Gamma \sim m$, leading to strong departures from the Breit–Wigner lineshape, distorted angular correlations, and significant modifications to both $s$- and $t$-channel dynamics. Comparing with the normal and complex-mass schemes, we find that standard treatments can substantially misestimate cross sections and kinematic distributions in the large-width regime. Our results show that existing collider limits on heavy neutrinos—and, more generally, on any broad resonance—should be revisited within a fully resummed framework, opening new opportunities for both experimental searches and theoretical model building.

Speaker: Yin-Fa Shen (Vanderbilt University (US))

15:15 Ubiquitous Corotation of Dark Matter Halos: Implications for Direct Detection

The ability of direct detection experiments to constrain dark matter properties depends sensitively on the phase-space distribution of dark matter near the Sun, which can be modeled theoretically with hydrodynamical simulations of Milky Way–like galaxies. In this work, we use a sample of nearly one hundred such galaxies from the TNG50 simulation to characterize the expected phase-space distribution of dark matter. In over 90% of halos, the dark matter at the Solar position co-rotates with the baryonic disk, with median azimuthal velocities of 12–39 km/s (16th–84th percentile). This reduces the expected geocentric dark matter flux by ~5% relative to the prediction from the Standard Halo Model, and the flux occupies a ~10% larger region on the sky. As a result, the rate of isotropic nuclear scattering in a fiducial Xenon-based detector can be diminished by up to 40% near threshold, and the expected reach of a directional detector is reduced by as much as 60% at peak sensitivity. The severity of this suppression is strongly correlated with the azimuthal velocity, and a determination of this quantity to within 20 km/s from studies of the Milky Way's formation history would reduce the velocity distribution–induced astrophysical uncertainty on the dark matter–nucleon scattering rate to as low as 5%.

Speaker: Dylan Folsom (Princeton University)

15:30 Hidden-Heavy Pentaquarks and Where to Find Them

The unexpected discovery of dozens of exotic heavy hadrons since 2003 has provided a major challenge to our understanding of QCD. Among the zoo of exotic hadrons are 3 hidden-charm pentaquarks and 2 strange hidden-charm pentaquarks, only one of whose quantum numbers has been determined. We provide a simple explanation for the observed hidden-charm pentaquarks as bound states in Born-Oppenheimer potentials for QCD. Our prediction for their J^}PC}quantum numbers differs substantially from most previous predictions.

Speaker: Fareed Alasiri

15:45 Phenomenological MSSM interpretation of CMS Run 2 searches

Results are presented for the combination of CMS Run 2 searches for new physics, interpreted in the framework of the phenomenological MSSM (pMSSM) via a scan over its 19-dimensional parameter space, using 138 fb⁻¹ of proton-proton collision data collected at 13 TeV. A global Bayesian analysis is performed, using a likelihood-based Markov Chain Monte Carlo (MCMC) approach incorporating data from CMS, as well as constraints from pre-LHC collider searches, the flavor sector, and Higgs mass measurements. In particular, the impact of the CMS search for the supersymmetric partners of tau leptons on the pMSSM parameter space is emphasized.

Speaker: Aleesha Kallil Tharayil (Carnegie-Mellon University (US))

14:15 → 16:00 New Developments in Theory: Session 1

14:15 A Geometric Path to Lorentz Spinors

Geometric algebra provides a natural extension of vector geometry that unifies rotations, boosts, and spinors within a single geometric framework. Starting from rotations in physical space, rotors emerge as the fundamental objects encoding orientation and transformation. This structure extends seamlessly to spacetime, where Lorentz boosts appear on equal geometric footing with spatial rotations. Within this language, spinors arise as concrete geometric entities associated with mass and motion rather than abstract algebraic constructs. The Lorentz spinor is introduced to establish the geometric foundation for a constructive formulation of relativistic quantum theory and, ultimately, particle physics.

Speaker: Zachary Gunther

14:30 Randall-Sundrum Dark Matter Portal Model - Symmetries, Amplitudes and Phenomenology

General Relativity (GR) is the classical interpretation of gravitational interaction. Equivalently, GR can be represented as an effective field theory (EFT) of the non-trivial self-interacting theory of a massless spin-2 particle. The Planck mass sets the high-energy cutoff, which is where we expect to see the effects of quantum gravity. Various modifications to gravity significantly lower the cutoff energy by increasing the scaling of tree-level amplitudes. For instance, standard massive gravity has scaling ~ s^5 / (m^8 x (M_Pl)^2), whereas the de Rham-Gabadadze-Tolley (dRGT) model of massive gravity ameliorates this with a lower scaling ~ s^3 / (m^4 x (M_Pl)^2), where s is the Mandelstam centre-of-momentum energy squared. A compactified five-dimensional theory of gravity both preserves the scaling behaviour of general relativity and generates an infinite tower of massive spin-2 fields. These properties arise from the spontaneous breaking of diffeomorphism invariance, leaving residual symmetries that preserve the 5D scaling in the 4D EFT.

This presentation investigates the surprising properties found in the scattering amplitudes of massive spin-2 Kaluza-Klein modes and analyses their origins in the hidden symmetries inherent to the compactified five-dimensional gravity framework. We will also briefly discuss an extension in which an intermediate brane is placed in the 5D bulk, along with the resulting amplitude properties.

The behaviour of dark matter is further explored within a stabilised Randall-Sundrum model, in which dark matter is localised on the TeV brane and interacts with both spin-2 Kaluza-Klein and spin-0 Goldberger-Wise modes. Constraints from relic density, collider searches, and direct-detection experiments strongly constrain spin-2 Kaluza-Klein portal models. Nevertheless, some regions of parameter space remain viable, primarily due to the effects of the massive radion arising from geometric stabilisation. These regions correspond to either a light (~1-5 GeV) or a heavy (~0.1-1 TeV) radion.

Speaker: Joshua Gill

14:45 Extensions Beyond 4-Point Amplitudes in Constructive QED

The field of particle physics constitutes the theoretical and experimental methods that we im-
plement to study the universe at the smallest fundamental scales. The current primary theoretical
framework that for electrons, positrons, and photons is Quantum Electrodynamics (QED). To com-
pare QED with experiment, it is necessary to calculate scattering amplitudes. The traditional
method of calculating amplitudes involves Feynman diagrams. Although sufficient in principle to
calculate any possible amplitude, it has been found that as the number of particles within a process
increases, both the number of Feynman diagrams as well as the complexity of calculating the dia-
grams grow to become too computationally expensive even for the most powerful supercomputers.
New techniques for calculating scattering amplitudes are needed. Constructive amplitudes are a
potential candidate with their own set of strengths and challenges. It has already been used to cal-
culate scattering amplitudes in QED for up to 4 particles. In this work, we extend these calculations
to diagrams beyond 4 particles. Our preliminary results are compact and show promising simpli-
fications of calculating scattering amplitudes. We will still work to validate these results against
Feynman diagrams as well as exploring other calculations.

Speaker: Nicholas Majestic (Illinois State University)

15:00 Dispersion relation and unitarization of electroweak amplitudes from continuous spectra and higher-spin towers

In this talk, I present a dispersive framework for unitarizing electroweak amplitudes using continuous spectral densities. Assuming fixed-angle UV softness, analyticity, crossing symmetry, and unitarity leads to sum rules that relate the infrared electroweak amplitude to positive spectral moments. For the $WWWW$ scattering process, the amplitude grows as $E^2$ if only gauge-boson contributions are included. I then show that the Higgs-like solution is not unique: one obtains an explicit infinite tower of neutral higher-spin states with non-negative moments that reproduces the same infrared behavior. For suitable spectral densities, the resulting amplitude reproduces the required low-energy electroweak limit and can remain UV-soft at fixed angle. These results clarify how continuum spectra and higher-spin towers can enter the dispersive unitarization of electroweak amplitudes.

Speaker: Chi Shu (University of Chicago)

15:15 Advanced maths in cosmology

In this talk, I will present recent advancements in mathematical and cosmological frameworks, drawing from my key studies. I will introduce functorial methods in Functors of Actions Theories (FAT), bridging mathematical rigor with cosmological phenomena, by predicting actionions [1,2]. Noticing the need of advanced math, I will introduce the exploration of novel tensor-based approaches from Advancing Tensor Theories (ATT) [3], and Advanced Manifold-Metric Pairs (AMMP) [4], offering new tools for modeling. ATT merges novel advanced indices, with corresponding tensors which are defined using standard calculus operators, and fractional calculus operators. AMMP introduces more abstract manifold metric pairs in which the line elements is constructured through a functional tensor of (U,L)-rank, rather than a (0,2)-rank, which opens a new road to introduce more sophisticated mathematical structure to physics problems. Finally, I will discuss the dynamics of the quintessence in the ϕCDM, simple ϕΛCDM, and a polyΛCDM models, providing insights into scalar field-driven cosmology and its implications for dark energy and modified gravity [5,6,7]. The analytical polyΛCDM model includes scalar-vector-tensor modified gravity theories to a lagrangian, and under appropriate assumption it results to a polynomial depenence in energy density ratios that can be measured by observational data, and distinguish which modified gravity model is more apparent from the background cosmology data. If time permits, I will talk about a novel test of fundamental principles of gravity in extra dimensions given large scale structure surveys with contaminated samples [8]. These works collectively highlight innovative mathematical methods to advance our understanding of the universe’s evolution and structure.

References:
1) Ntelis P. & A. Morris. 2023. Functors of Actions. Foundations of Physics. available at: https://arxiv.org/abs/2010.06707
2) Ntelis P. 2025 CosmoFATs. under review. available at https://www.preprints.org/manuscript/202506.0322/v1
3) Ntelis, P. 2025. Advancing Tensor Theories. Symmetry: Mathematics: Advances in Topology and Algebraic Geometry. Available at: https://www.mdpi.com/2073-8994/17/5/777
4) Ntelis, P. 2025. Advanced Manifold-Metric Pairs. MDPI Mathematics. Available at: https://www.mdpi.com/2227-7390/13/15/2510
5) Ntelis, P. & J. L. Said. 2025. Analytical polyΛCDM dynamics. Physics of the Dark Universe, available at: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=5243299
6) Ntelis, P. & J. L. Said. 2025. Exploring ϕCDM Model Dynamics. The European Physical Journal C. arXiv:2502.03486, available at: https://arxiv.org/abs/2502.03486
7) Ntelis, P. & J. L. Said. 2025. Simple ϕΛCDM Dynamics. International Journal of Geometric Methods in Modern Physics. Available at: https://www.researchgate.net/publication/391905442_Simple_phiLambdaCDM_dynamics
8) Ntelis, P. 2022-2026. A (Dτ,Dx)-manifold with N-correlators of Nt-objects. International Journal of Geometric Methods in Modern Physics. arXiv:2209.07472, available at: https://arxiv.org/abs/2209.07472

Speaker: Pierros Ntelis (Harbin Institute of Technology)

15:30 The Geometric Scattering Algebra of Physical Space

The geometric Algebra of Physical Space (APS) has recently been used to explore the Constructive Standard Model (CSM) of particle physics. Namely, the spinor formalism of the APS was rigorously tied to the CSM via a tool called the Scattering Algebra (SA). Significant insights were discovered: That the CSM's spin spinors (massive helicity spinors) are matrix representations of the APS' Lorentz spinors (scaled Lorentz transformations); and that the CSM is connected to various formalisms through lightray spinor structure.

The language of the APS' geometry is simple and visualizable: All objects have straightforward geometric interpretations that can be drawn by hand and explained to someone with no background. This vastly improves the accessibility of the subject and is a first step to simplifying the field.

Speaker: Moab Croft (Illinois State University)

15:45 Holographic Chiral Anomalies and Axions Phenomenology

The structure of chiral anomalies in brane world models presents subtle but important features. While the divergence of a 5D current has long been known to localize to end-of-the-world branes and distribute evenly between them, this picture breaks down when branes are hidden by horizons or replaced by soft-wall geometries. We demonstrate that in models motivated by the AdS/CFT correspondence — including Randall-Sundrum constructions — the correct approach is to introduce Chern-Simons terms that flow the anomaly entirely onto the ultraviolet, or "cut-off," brane. This has interesting implications both for collider physics and for cosmology. We discuss the implications for holographic composite axion solutions to the strong CP problem, and for inflationary cosmology.

Speaker: Hanieh Moradipasha (Syracuse university)

14:15 → 16:00 New Ideas in Baryogenesis, Inflation

14:15 Axiverse Baryogenesis

I will review the idea of correlating the dark matter and the baryon asymmetry abundances in a QCD dark matter model, i.e. axiogenesis. I will highlight some of the shortcomings of this idea, and propose a setup circumventing them.

Speaker: Pouya Asadi (UCSC)

14:30 Gravity’s Gift: Baryons from the Big Bang

This talk is based on a recent paper in which my collaborators and I have explored how the cosmological excess of matter over antimatter can arise through the phenomenon of cosmological gravitational particle production at the end of inflation in a Type-I Seesaw model of nonthermal leptogenesis. From a model-building standpoint, this scenario is appealing for being minimal and economical, since some amount of gravitational production is unavoidable. From the phenomenological perspective, this scenario links the observed baryon asymmetry to the energy scale of inflation and the amplitude of inflationary gravitational waves. A non-detection of in measurements of CMB polarization would rule out this model.

Speaker: Andrew Long (Rice University)

14:45 Lingering to Inflation and the Hagedorn Phase Transition

We investigate the Hagedorn regime of string theory as a possible origin for a cosmological loitering phase preceding inflation. Working with a homogeneous gravi-dilaton background coupled to an effective thermal scalar $\chi$ representing the dominant winding sector, we perform a complete phase-space analysis across three regimes of the temperature-dependent mass parameter $\mu^2$. We show that loitering configurations arise for $\mu^2 > 0$, where the thermal scalar's potential energy balances the dilaton kinetic energy. On the $(-)$ branch, dilaton coupling provides a friction mechanism that drives $\dot{\chi} \to 0$, but these states are not generic attractors --- they appear as threshold configurations on the boundary of the allowed phase space. We argue that $\mu^2$ must depend on the scale factor, and that additional physics is required to sustain the loitering phase long enough to serve as a robust precursor to inflation.

Speaker: Luis Rufino (Syracuse University)

15:00 Non-Gaussianity in Warm Inflation

Inflaton couplings to the radiation bath source inflaton fluctuations that are predominantly thermal in origin. In the context of pseudoscalar couplings, a chemical potential is induced in the bath due to non-conserved charges, which significantly modifies both the thermal friction acting on the inflaton and its associated fluctuations. In particular, the chemical potential alters the fluctuation-dissipation theorem and thereby modifies the resulting power spectrum, making it model-dependent. In previous work, we captured this effect on the friction and noise coefficients, demonstrating that the corrections can be order-one and thus non-negligible. Building on these results, we systematically investigate the non-Gaussianities generated at leading order in the inflaton-bath coupling constants, revealing multiple novel contributions to the primordial bispectrum. One such source, not previously considered, stems from chemical-potential-induced higher-order corrections to the friction term. Incorporating these corrections, we further show that thermal expectation values reduce to a classical limit in the zero-width limit for bath correlators, with implications for the shape and amplitude of the primordial bispectrum.

Speaker: Sagnik Mondal (Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, MD 20742, U.S.A.)

15:15 The Entangled State from a cosmological Euclidean Wormhole

We use the Euclidean path-integral method to approximate the wave function of the Universe and consider the particular scenario in which a Euclidean wormhole instanton dominates. This Euclidean wormhole solution connected to Lorentzian manifolds provides an approximation to the emergence of a classical spacetime in the quantum cosmological treatment. Beyond the background level, perturbations built on top of this instanton solution are treated quantum mechanically in both the Euclidean and Lorentzian regimes. Due to the existence of a Euclidean wormhole bridging the twin universes, the perturbations of each universe is then in a mixed-state and the mutual entanglement shall leave signatures in the cosmic microwave background (CMB) power spectrum. Invoking the Klebanov-Susskind-Banks wormhole as a toy model for the sake of tractability, we show that the entanglement selects a novel and unique non-thermal global vacuum for the total inflaton perturbations in both universes.

Speaker: Wei-Chen Lin (Ewha Womans University)

15:30 Stochasticity in reheating

The viability of cosmic inflation depends on an efficient reheating phase that converts the inflaton's energy into Standard Model particles. This conversion preferably proceeds through non-perturbative resonance, which is described by Hill's equation. In this talk, I’ll show how stochastic fluctuations in the parameters of Hill's equation can influence particle production during reheating. Such fluctuations can arise from couplings to light scalar fields, and can alter the resonance structure, thereby broadening the region of efficient energy transfer. These results suggest that stochastic effects can robustly enhance the efficacy of reheating over a broader parameter space than the noiseless case. The applicability of this result extends to similar issues such as the cosmological moduli problem.

Speaker: Leia Price (MIT)

15:45 The Extra-dimensional Origins of the Chemical Potential at the Cosmological Collider

We study the realization of the chemical potential mechanism in cosmological collider physics in a robust model of inflation arising from multiple extra-dimensional gauge fields. We show that particles heavier than the inflationary Hubble scale can be created without suppression through minimal gauge interactions as the rolling inflaton background corresponds to an electric field in the extra dimension in which charged particles are produced analogously to the Schwinger mechanism. We also demonstrate how realistic models consistent with both theoretical and experimental constraints can be constructed along these lines.

Speaker: Zhaohui Xu (University of Maryland, College Park)

14:15 → 16:00 New Physics at Future Colliders: Higgs, SUSY

14:15 Searches for electroweak production of supersymmetric particles with the ATLAS detector

The direct production of electroweak SUSY particles, including sleptons, charginos, and neutralinos, is a particularly interesting area with connections to dark matter and the naturalness of the Higgs mass. The small production cross-sections and challenging experimental signatures lead to difficult searches. This talk will highlight the most recent results of searches performed by the ATLAS experiment for supersymmetric particles produced via electroweak processes, including analyses targeting small mass splittings between SUSY particles. Results are interpreted in terms of SUSY simplified models and, for the first time since the LEP era, several gaps in different ranges of mass-splittings are excluded.

Speaker: Evelyn Jean Thomson (University of Pennsylvania (US))

14:30 Searches for long-lived particles and unconventional signatures with CMS

Many models beyond the standard model predict new particles with long lifetimes. These long-lived particles (LLPs) decay significantly displaced from their initial production vertex thus giving rise to non-conventional signatures in the detector. Dedicated triggers and innovative usage of the CMS detector boost are exploited in this context to significantly boost the sensitivity of such searches at CMS. We present recent results of searches for long-lived particles and other unconventional signatures such as black holes, obtained using data recorded by the CMS experiment during the Run-II and Run-III of the LHC.

Speaker: Gianfranco De Castro (Cornell University (US))

14:45 Real singlet scalar benchmarks in the multi-TeV resonance regime

Scalar extensions of the Standard Model are of much interest at the Large Hadron Collider and future colliders. In particular, these models can give rise to resonant di-Higgs production and alter the Higgs trilinear coupling. In this talk, we study di-Higgs production in the Standard Model extended by a real scalar singlet with no additional symmetries. We determine how large the resonant di-Higgs rate and variation in the Higgs trilinear coupling can be in four scenarios: current LHC results and projected results at the high luminosity LHC (HL-LHC), the HL-LHC combined with a circular e-e+ collider such as the Future Circular Collider with electron-positron collisions, and the HL-LHC combined with a linear e-e+ collider such as the International Linear Collider. We find benchmark points in the multi-TeV resonance regime for future colliders beyond the HL-LHC. Considering current LHC results, the resonant di-Higgs rate can still be an order of magnitude larger than the SM predicted di-Higgs rate. In the HL-LHC scenario, the Higgs trilinear coupling can still be a factor of three larger than the SM prediction for resonance masses in the 1.5–3.5 TeV range, where resonant searches may have less reach. This enhancement is just at the projected 2σ sensitivity of the HL-LHC. We find there are resonance masses for which the change in the Higgs trilinear is maximized while the resonant rate is negligible.

Speaker: Ian Lewis (The University of Kansas)

15:00 Top Quark Pair Production and Decay: The 1-Higgs-Singlet Model and Pseudoscalar Decay

The process of top quark pair production via the decay of the scalars in the 1-Higgs-Singlet extension of the Standard Model is associated with large interference effects between the loop-induced SM-like Higgs and heavy Higgs amplitudes, and the QCD continuum background. We attach leptonic decays to the di-top final state at NLO and study the effects of spin correlation in the process. We also make phenomenological predictions for the leptonic decays of the top quark pair produced via the decay of a CP-odd pseudoscalar at the LHC at NLO accuracy, with the full spin correlation effects preserved in the decayed products. We attach parton showers and perform analyses of differential cross sections as functions of various parameters to study the significance of the results in searches for new scalars and pseudoscalars beyond the Standard Model.

Speaker: Vishakha Lingadahally

15:15 Higgs decays to four leptons to $\mathcal{O}(1/\Lambda^4)$ in SMEFT

We study the decays $h \to \ell \bar{\ell} \left(Z \to \ell' \bar{\ell'}\right)$ and $h\to\ell\bar{\nu}_\ell\nu_{\ell'}\bar{\ell'}$ within the SMEFT framework and including effects up to $\mathcal O(1/\Lambda^4)$, where $\Lambda$ is the new physics scale suppressing higher dimensional operators. To work to this order, we must include the square of dimension-six operators and the interference of dimension-eight operators with the Standard Model. We study angular asymmetries and other differential decay observables and determine which are most sensitive to $\mathcal O(1/\Lambda^4)$ effects. While new kinematic structures arising in higher dimensional operators have the potential to induce novel angular dependency, we find this does not occur for $h\to\ell\bar{\ell}\left(Z\xrightarrow{}\ell'\bar{\ell'}\right)$. For $h \to \ell \bar{\nu}_\ell \nu_{\ell'} \bar{\ell'}$, new angular dependencies do arise at $\mathcal O(1/\Lambda^4)$, though they require a fully reconstructible (meaning we can go to the Higgs rest frame) final state. For non-reconstructible final states such as $\ell \bar{\nu}_\ell \nu_{\ell'} \bar{\ell'}$, we must study Higgs production and decay together with the appropriate observables, which we find obscures the new angular effects.

Speaker: Mario Flores-Hernández (University of Notre Dame)

15:30 Photon‑Induced Triple Higgs Production in the Higgs Triplet Model at Muon Colliders

Double- and triple-Higgs production provides direct access to the Higgs trilinear and quartic self-couplings, which determine the structure of the Higgs potential. Measuring these couplings is challenging at the LHC due to small production rates and luminosity requirements, particularly for the quartic interaction. Future muon colliders, with higher center-of-mass energies and cleaner environments, offer improved sensitivity to multi-Higgs processes.
We study triple Higgs boson production via photon fusion from high-energy muon beams at the one-loop level, using the Effective Photon Approximation to compute total cross sections. Our analysis is performed in both the Standard Model and the Higgs Triplet Model, where the mass hierarchy of charged Higgs states can significantly affect the rates. Results are presented for center-of-mass energies of 3, 10, and 100 TeV, using amplitudes generated with FeynRules, GoSam, FeynArts, and FormCalc.

Speaker: Terrance Figy (Wichita State University)

15:45 Exotic Higgs Decays at a Muon Collider

We study the prospects for probing exotic Higgs decays at a future muon collider in a minimal extension of the Standard Model with a light singlet scalar $S$. We focus on the process $h \to SS$ and consider two representative final states, $4b$ and $2b2\mu$. Our analysis is performed for muon collider benchmark scenarios at $\sqrt{s}=3~\mathrm{TeV}$ with $1~\mathrm{ab}^{-1}$ and $\sqrt{s}=10~\mathrm{TeV}$ with $10~\mathrm{ab}^{-1}$. Signal and background events are simulated using a full analysis chain, and machine-learning techniques are employed to improve background rejection and reduce jet combinatorics ambiguities. We find that the $4b$ channel can probe branching fractions $\mathrm{BR}(h \to SS \to 4b)$ at the level of $\mathcal{O}(10^{-2})$ at $3~\mathrm{TeV}$ and $\mathcal{O}(10^{-3})$ at $10~\mathrm{TeV}$, substantially extending the projected reach of the HL-LHC. The $2b2\mu$ final state benefits from a clean dimuon resonance and can reach sensitivity to $\mathrm{BR}(h \to SS \to 2b2\mu)$ at the $10^{-5}$ level at a $10~\mathrm{TeV}$ muon collider. These results demonstrate the strong potential of a high-energy muon collider for exploring exotic Higgs decays and light scalar sectors beyond the Standard Model.

Speaker: Yanhan Wang (Brown University)

16:00 → 16:30 Coffee Break

16:30 → 18:30 Astro-particle: BSM, Cosmic Rays

16:30 Astrophysical Consequences of an Electroweak ηw Pseudo-Scalar

It has recently been proposed that the Standard Model may include
an ultralight pseudo-scalar, ηw, emerging from electroweak interactions. We find that typical expectations for the properties of ηw get challenged by astrophysical constraints on the couplings of ultralight bosons.

Speaker: Hooman Davoudiasl

16:45 Neutron Star Eclipses as Axion Laboratories

Axion-like particles (ALPs) appear in many beyond-the-Standard-Model theories, either as candidates for dark matter or as partners of the axion that explains the apparent conservation of charge-parity symmetry, known as the strong CP problem. In this talk, I will present a novel method for probing ALPs using eclipsing binary systems which can serve as an astrophysical realization of light-shining-through-walls experiments. Such systems are composed of a neutron star that is bright in X-rays and a larger companion star, through which ALPs produced via conversion in the neutron star's magnetosphere can pass during the eclipse. The ALPs then partially reconvert into photons in the interstellar medium on their way to Earth, and the resulting X-rays are detectable by space observatories such as XMM-Newton.

Speaker: Vedran Brdar (Oklahoma State University (US))

17:00 Discovering Isolated Neutron Stars with the Vera Rubin Observatory

Isolated neutron stars (INS) are the simplest kinds of neutron stars, but only seven have been discovered and confirmed. We show that in the near future, the Vera Rubin Observatory (VRO) will be able to identify new INS candidates. In this talk, we outline a proof of concept for predicting the signals from INS as seen by VRO, as well as a method for separating those signals from backgrounds. We show that there are opportunities not only for the discovery of new objects, but also for constraining the microphysics of degenerate nuclear matter.

Speaker: Shirley Li (UC Irvine)

17:15 Efficient PINN Models of Cosmic Rays

The Galactic Center GeV excess is one of the most promising indirect detections of dark matter, but robust interpretation of the signal is bottlenecked by the cost of simulating the cosmic-ray-induced $\gamma$-ray background. It is intractable to run the gold-standard GALPROP code over the full space of plausible propagation models, whose cosmic-ray distributions are highly uncertain and sensitive to physics across many energy scales. As a proof of concept, we train lightweight Physics-Informed Neural Networks (PINNs) that directly learn the solution to the cosmic-ray transport equation for primary $e^-$ over energies from 100 MeV to 1 PeV. We demonstrate that PINNs can emulate the GALPROP solution to high accuracy at substantially lower computational cost during both training and inference, and in some cases offer more reliable convergence to the equilibrium cosmic-ray flux.

Speaker: Eric Putney (Rutgers University)

17:30 Constraining Galactic Cosmic Ray Models with a Multi-Messenger Analysis of the Diffuse Emission

The origin of Galactic Cosmic Rays (GCRs) up to the PeV energy scales remains a significant question in astrophysics. As charged particles, GCRs are deflected by galactic magnetic fields, obscuring their sources. However, the interactions of GCRs with interstellar gas produce a diffuse flux of high-energy gamma rays and neutrinos. This talk will investigate the origins of GCRs by performing a comprehensive multi-messenger analysis. We will employ a range of six theoretical models describing neutral pion decay to predict diffuse gamma-ray emission from the Milky Way. For each model, a corresponding neutrino flux will be derived. These predictions will be tailored to specific regions of the sky, including the inner (25°< l < 100°, ∣b∣ < 5°) and outer (50°< l < 200°, ∣b∣ < 5°) galaxy.
The resulting gamma-ray and neutrino spectra will be compared with the latest observational data from LHAASO and IceCube. This comparative study aims to constrain GCR propagation models and to search for potential unresolved source populations, such as TeV Halos. We find that for most models, TeV halos do not contribute significantly above ~1 TeV; consequently, the respective neutrino emissions are heavily dominated by point sources of unknown origin.

Speaker: Alisha Roberts (University of Wisconsin-Madison)

17:45 Seeing the Invisible: Mini-CoRTEx and Real-Time 3D Visualization of Cosmic-Ray Muons

We present Mini Cosmic Ray Tracker Experiment (Mini-CoRTEx), a portable plastic scintillator-based detector designed for three-dimensional tracking and real-time visualization of cosmic-ray muons. The system consists of eighteen plastic scintillator tiles, each instrumented with wavelength-shifting fibers and silicon photomultipliers, arranged in three stacked layers with orthogonal x-y segmentation to form a 3x3x3 tracking geometry. Custom multichannel front-end electronics provide signal amplification and discrimination, while a field programmable gate array chip (FPGA) performs coincidence triggering and event counting across the detector layers. The triggered data are transmitted to a Raspberry Pi, where muon trajectories are reconstructed and extrapolated from the physical detector volume to a virtual 8x8x8 grid. The reconstructed tracks are displayed on a digital twin realized by a three-dimensional LED cube in real-time, enabling direct and intuitive visualization of cosmic-ray muon paths. By transforming detector signals into visible spatial tracks, the system serves as an effective platform for public outreach, exhibitions and education in particle physics, while also supporting quantitative measurements of cosmic muon flux and angular distributions in different environments.

Speaker: Yuvaraj Elangovan (University of Pittsburgh (US))

18:00 Naturalness in Soft SUSY Leptogenesis and Gravitino Mass Bound due to PBH

If sneutrinos are produced through primordial black hole (PBH) evaporation, then some interesting features of soft leptogenesis in the Minimal Supersymmetric Standard Model with heavy right-handed neutrinos, are found. The required baryonic asymmetry could be possible from the decays of sneutrinos, for the soft SUSY breaking trilinear $A$ and bilinear $B$ parameters around the electroweak scale. The resonance condition in soft leptogenesis is not required. The allowed regions of different relevant parameters are discussed in detail. Using experimental constraints from collider searches on heavy leptons, the lower bound on the right-handed neutrino mass is found to be around
$300$ GeV with Yukawa coupling lesser than about $0.4$.
The allowed region of the typical mass scale of some supersymmetric particles and the $|A|$ parameter is also shown from the experimental constraint on the branching ratio for $\mu \rightarrow e \gamma$ in MEG \RN{2} search.
Depending on PBH mass, bounds on the mass of gravitinos,
produced from PBH evaporation, is discussed and gravitino mass around the electroweak scale is found to be possible only for unstable gravitino.

Speaker: SUHAIL KHAN (Centre for Theoretical Physics,Jamia Millia Islamia, New Delhi, India)

18:15 Monopole phenomenology from the electroweak anomaly

Magnetic monopoles are well known to catalyze baryon number violating processes in grand unified theories through the Callan–Rubakov effect. More generally, however, monopoles participating in the electroweak anomaly can catalyze processes with ΔB=ΔL=3. In this talk, I will present a first phenomenological exploration of such monopole-induced processes in different physical settings. I will highlight the experimental signatures that arise from this mechanism and discuss new experimental detection strategies motivated by these phenomena.

Speaker: Jiawei (Vivian) Gao (UCSB)

16:30 → 18:30 Cosmology: Bosonic fields

16:30 EFT perspective on fifth-force searches using isotope shift spectroscopy

Precision spectroscopic measurements of isotope shifts have recently reached a high level of accuracy. Tests of King non-linearity (NL) along isotope chains have been proposed as a tool to search for fifth-force mediators. At the same time, these tests can potentially teach us about the structure of heavy nuclei at unprecedented precision, where
King NL has already been observed in several systems. A robust interpretation of the existing data, however, is hampered by incomplete control over the Standard Model (SM) contributions. We develop a systematic effective field theory framework, matching the SM onto scalar non-relativistic QED in the infinite nuclear mass limit and then onto quantum-mechanical potentials. This approach organizes all nuclear effects into a small set of Wilson coefficients and cleanly separates short- and long-distance physics. We show that the commonly used treatment of the <r^2>^2 term needs to be reconsidered, as it arises only at second-order in perturbation theory, and we derive the long-range 1/r^4 potential from nuclear polarizability. Applying the framework to hydrogen-like systems, we provide a transparent classification of SM sources of King NL relevant for current and future isotope-shift experiments. The formalism can be applied to learn about the shape of the heavy scalar nuclei at a higher level of precision and detail than what was previously attainable.

Speaker: Gil Paz

16:45 Composite Ultralight Scalars, Fifth Forces, and Atomic Clocks

We consider fifth forces mediated by an ultralight scalar that arises as a composite pseudo-Nambu-Goldstone boson from a strongly coupled hidden sector. In our framework, the scalar couples to the Standard Model through the hypercharge portal, and its interactions are softened above the compositeness scale by form factors. This can significantly weaken conventional equivalence principle (EP) bounds, especially when the compositeness scale lies between atomic and nuclear scales. We find that clock-based searches can become the leading probe of this scenario, with atomic clocks already more sensitive than traditional EP tests in parts of parameter space — and even outperforming nuclear clocks. These results highlight atomic clock experiments as a powerful, broadly motivated approach to searching for new fifth forces.

Speaker: Shourya Mukherjee

17:00 Cosmological constraints on Majoron Dark Matter

In this talk, we look at some cosmological constraints on majoron dark matter in the singlet Majoron model. We consider two scenarios: pre-inflationary and post inflationary spontaneous lepton number symmetry breaking, while simultaneously demanding leptogenesis to happen, and neutrino masses being generated by the type I seesaw mechanism. We derive the constraints and future prospects to probe majoron dark matter over a broad mass range.

Speaker: Swapnil Dutta

17:15 Constraining Dark First-Order Phase Transitions with CMB and Structure Formation Observations

Cosmological first-order phase transitions (FOPT) can occur in a secluded dark sector at relatively late times before recombination. Since bubble nucleation occurs stochastically as the FOPT unfolds, different regions of the universe transition at different times. On large scales, this random fluctuation sources a scalar curvature perturbation with a dimensionless power spectrum that scales independently of the microscopic details of the FOPT. Even though the dark sector interacts with the Standard Model only gravitationally, the generated curvature perturbation can affect various cosmological and astrophysical observables. In this talk, we consider how such an FOPT can be constrained at different scales using CMB and structure formation measurements.

Speaker: Daven Wei Ren Ho

17:30 Computing bubble wall velocity from entropy

A precise determination of the bubble wall velocity $v_w$ is crucial for making accurate predictions of the baryon asymmetry and gravitational wave (GW) signals in models of electroweak baryogenesis (EWBG).
Working in the local thermal equilibrium approximation, we exploit entropy conservation to present efficient algorithms for computing $v_w$, significantly streamlining the calculation.
We then explore the parameter dependencies of $v_w$, focusing on two sample models capable of enabling a strong first-order electroweak phase transition: a $\mathbb{Z}_2$-symmetric singlet extension of the SM, and a model for baryogenesis with CP violation in the dark sector.
We study correlations among $v_w$ and the two common measures of phase transition strength, $\alpha_n$ and $v_n/T_n$.
Interestingly, we find a relatively model-insensitive relationship between $v_n/T_n$ and $\alpha_n$.
We also observe an upper bound on $\alpha_n$ for the deflagration/hybrid wall profiles naturally compatible with EWBG, the exact value for which varies between models, significantly impacting the strength of the GW signals.
In summary, our work provides a framework for exploring the feasibility of EWBG models in light of future GW signals.

Speaker: Isaac Wang

17:45 Effects of New Forces on Scalar Dark Matter Solitons

New long range forces acting on ordinary matter are highly constrained. However it is possible such forces act on dark matter, as it is less constrained observationally. In this work, we consider dark matter to be made of light bosons, such as axions. We introduce a mediator that communicates a new force between dark matter particles, in addition to gravity. The mediator is taken to be light, but not massless, so that it can affect small scale galactic behavior, but not current cosmological behavior. As a concrete application of this idea, we analyze the effects on scalar dark matter solitons bound by gravitation, i.e., boson stars, which have been claimed to potentially provide cores of galaxies. We numerically determine the soliton's profiles in the presence of this new force. We also extend the analysis to multiple mediators. We show that this new force alters the relation between core density and core radius in a way that can provide improvement in fitting data to observed galactic cores, but for couplings of order the gravitational strength, the improvement is only modest.

Speaker: Alize Sucsuzer (Tufts University)

18:00 Understanding Misaligned Condensates with Yukawa Couplings

We study the dynamics of a spatially homogeneous scalar (or pseudoscalar) condensate Yukawa-coupled to N_f fermionic degrees of freedom, with emphasis on the real-time processes governing misalignment, particle production, and entropy generation. Going beyond the effective potential framework, we develop a dynamical treatment in which the scalar condensate and fermionic sector are evolved self-consistently within a Hamiltonian formulation that preserves energy conservation and incorporates backreaction. In the large-N_f​ limit, the fermionic fluctuations provide a controlled quantum bath that drives dissipative and non-adiabatic effects in the condensate dynamics. We implement a systematic adiabatic expansion to separate instantaneous effective potential contributions from genuine dynamical effects such as particle production, field renormalization, and memory-dependent corrections. We show that Yukawa interactions lead to significant fermion production, which in turn induces damping and reshaping of the condensate evolution. The resulting energy transfer generates entropy and drives the system toward a highly excited late-time regime characterized by non-thermal particle distributions and scaling behavior. In this framework, the standard effective potential emerges as the leading adiabatic approximation, while higher-order terms encode irreversible dynamics absent in equilibrium descriptions. Our results demonstrate that misaligned condensates coupled to fermions can exhibit emergent nonequilibrium phenomena, including dynamical symmetry breaking and entropy growth, highlighting the importance of fully real-time treatments in cosmological and particle physics settings where scalar fields interact with fermionic sectors.

Speaker: Nathan Herring (Hillsdale College)

18:15 Emergent modified gravity: Dynamical dark energy model without additional degrees of freedom

Cosmological models of emergent modified gravity allow departures from the dynamics of general relativity in the high and low-curvature regimes without additional degrees of freedom. Consequently, emergent modified gravity is not only able to replace the big bounce singularity with a nonsingular bounce from a purely modified gravity perspective without exotic matter fields, but also to reproduce the late-time expansion rate that is commonly attributed to the effects of a weakening dark energy by the introduction of a modification function of the phase space in the Hamiltonian.

Speaker: Manuel Diaz

16:30 → 18:30 Dark Matter: Direct Detection

16:30 Latest Results of the LUX-ZEPLIN (LZ) Dark Matter Experiment

LUX-ZEPLIN (LZ) is a dark matter direct detection experiment located 4,850 feet underground at the Sanford Underground Research Facility (SURF) in South Dakota. The detector is a dual-phase Time Projection Chamber (TPC) that utilizes 7 tonnes of liquid xenon (LXe) as its target medium to search for dark matter interactions, primarily from the highly-motivated candidate Weakly Interacting Massive Particles (WIMPs), as well as from some other candidates beyond the Standard Model. LZ continues to constrain parameter-space for dark matter as it acquires more data towards its goal of 1,000 days of live time. This talk will present LZ’s new 3 – 9 GeV/c² light dark matter search results, where LZ is world-leading above 5 GeV/c², along with the most significant evidence to-date for solar boron-8 coherent elastic neutrino-nucleus scattering in LXe TPCs.

Speaker: Jack Genovesi (Pennsylvania State University)

16:45 AI-Driven Material Discovery in a Pipeline to Develop DM Detectors

The systematic discovery of optimal sub-GeV dark matter targets, such as anisotropic molecular crystals, is bottlenecked by the computational cost of evaluating complex many-body scattering form factors. In this talk, I will present a novel machine learning framework designed to overcome this barrier by high-throughput screening through the vastness of material space. I will detail how we couple a generative material discovery model with a bespoke electronic-structure computational framework, to perform fast validation of candidate materials. I will discuss how this pipeline allows us to efficiently identify next-generation detector targets sensitive to the directional dark matter wind and how these calculations have accelerated their deployment in recent experimental efforts.

Speaker: Carlos Blanco

17:00 Sub-GeV Dark Matter Detection with Dark Rates in Liquid Scintillators

It was recently shown that standard sub-GeV dark matter candidates can be effectively probed by large neutrino observatories via annual modulation of the total photomultiplier hit rate. That work focused on the production of light by the excitation of scintillator molecules and considered the JUNO detector, surpassing limits from dedicated dark-matter detectors and reaching theoretical targets. Here, we significantly generalize that work, now also taking into account ionization channels and extending the analysis to other liquid-scintillator detectors, including SNO+, Daya Bay, Borexino, and KamLAND. Last, we present a call to action: with multiple detectors achieving competitive sensitivity, there is an opportunity to validate this new technique across experiments and to refine it using each detector’s strengths.

Speaker: Lillian Santos-Olmsted

17:15 Dark matter-electron scattering with RPA dielectric screening

Accurate predictions for dark matter-electron scattering in solids require an all-electron treatment together with a faithful description of dielectric screening beyond simple approximations. We compute scattering rates that incorporate dielectric screening at the random-phase approximation (RPA) level, including local field effects, with our updated code QCDark2. We show the impact of local field effects both at large momentum transfers relevant to halo dark matter, and at low momentum near the plasmon resonance, relevant to boosted dark matter.

Speaker: Megan Hott (Stony Brook University)

17:30 Strategies for Next-Generation sub-GeV Direct Detection

Anisotropic direct detection experiments can discover dark matter even in the presence of irreducible Standard Model backgrounds, by using daily modulation to isolate the dark matter signal. Our new ab initio molecular physics package, SCarFFF, makes it possible to sift through millions of molecules to find the ones best suited for dark matter detection. What properties should we be looking for? In this talk, I show how an ensemble of different materials could provide the foundation for an unambiguous discovery of dark matter, and I explain why the ideal detector should include both parity-breaking and parity-symmetric materials.

Speaker: Benjamin Lillard (Pennsylvania State University)

17:45 Dive deeper with SUBMARINE: SUB-Mev dArk matter diRect detectIon using bilayer grapheNE

Novel target materials with anisotropic response will play a key role in
detecting low-mass dark matter in upcoming experiments. Bilayer graphene is one
such material that has been proposed for the detection of sub-MeV mass dark
matter particles via electronic excitations. In this work, we calculate
scattering rate via a massive mediator in bilayer graphene. With an exposure as
small as $\sim$ 0.5 mg-year, bilayer graphene can probe new regions of the
parameter space. The anisotropic response function of bilayer graphene leads to
a sidereal-day modulation in the scattering rate, depending on its orientation
with respect to the Galactic dark matter wind. We find significant modulation
in the scattering rate for sub-MeV mass dark matter, demonstrating bilayer
graphene's promise for a future experiment. We hope that our work will motivate
the community to investigate bilayer graphene as a novel target material, and
that it may lead us to discover the particle nature of dark matter.

Speaker: Anuvab Sarkar

18:00 Millicharged Particle Direct Detection Using Optimized Ion Traps

We describe how to optimize ion traps to function as direct detectors of millicharged particles. Although new particles with electric charge O(1) are heavily constrained, particles with lower charges are much less tightly constrained. These millicharged particles could have charges from about 0.1 down to 10^{-6} and can exist over a wide range of masses, starting at about 10 MeV. Few experiments exist which are capable of directly detecting millicharges over much of this parameter space. We detail how to use ion traps as quantum detectors with extremely low energy thresholds and suppressed standard model backgrounds. The quantum level (cyclotron mode) of the trapped ion can be read out quickly and non-destructively and used to look for interactions between the trapped ion and a single scattering millicharge. Looking for jumps of multiple cyclotron levels reduces the background while allowing us to increase the sensitivity of the trap by multiple orders of magnitude. This gives an experimental design which will be newly sensitive to particles across a wide range of masses and charges. In a section of this parameter space, the particles would constitute an irreducible signal population, produced from cosmic rays in Earth’s atmosphere.

Speaker: Jonathan Shoemaker (Stanford University)

18:15 Cavendish Searches for Millicharged Particles

A terrestrial population of millicharged particles can arise if they constitute a subcomponent of dark matter, or if sufficiently light millicharged particles are produced in cosmic-ray air showers. Through repeated scattering with ordinary matter, these particles thermalize to terrestrial temperatures in Earth’s environment. I will show that a simple electrified shell, such as a Van de Graaff generator, acts as an efficient accumulator of these room-temperature particles and can enhance their local density by up to twelve orders of magnitude. A millicharge detector placed inside the shell can therefore gain a dramatic boost in sensitivity. In particular, Cavendish tests of Coulomb’s law act naturally as both accumulators and detectors of this overdensity. Reinterpreting past Cavendish experiments already yields some of the strongest bounds on terrestrial millicharged-particle populations. I will also discuss a modified setup in which the Cavendish apparatus is surrounded by an additional charged shell, substantially improving the reach and potentially enabling detection of the minimum density generated by cosmic rays. With established electrostatic technology, such experiments can surpass the projected sensitivity of future accelerator searches for sub-GeV masses.

Speaker: Zachary Bogorad (Fermilab)

16:30 → 18:30 Dark Matter: Theory

16:30 Dark Matter during First-Order Phase Transitions

We consider a dark sector consisting of fermionic dark matter (DM) charged under a broken dark $U(1)_D$ gauge symmetry, interacting with the Standard Model through kinetic mixing. In such models, the DM annihilation cross section is typically suppressed by the small kinetic mixing and or a heavy mediator, often leading to an overabundant relic density. We show that the observed DM abundance can be achieved if the dark Higgs undergoes a strong first order phase transition after DM freeze-out. In this scenario, the relic abundance is set by thermal freeze-out in the symmetric phase and subsequently reduced by entropy injection from the phase transition, rather than by annihilation in the broken phase. We find that to reproduce the observed relic abundance, the required phase transition is generically supercooled. The resulting stochastic gravitational wave signal lies within the sensitivity of future experiments, providing a complementary probe of this framework. Moreover, a strongly supercooled phase transition can potentially account for the NANOGrav signal for DM masses below $\mathcal{O}(10)$ GeV.

Speaker: Peisi Huang

16:45 WIMPs with Enhanced Annihilation from a Feebly Interacting Unstable Partner

Weakly interacting massive particles (WIMPs) remain a well-motivated dark matter candidate. We study a minimal extension in which WIMPs are coupled to a heavier, feebly interacting partner that decays into them. In the early Universe, WIMPs in thermal equilibrium with the Standard Model serve as a portal to produce this heavy partner population. If the partner thermalizes and decays before WIMP freeze-out, the standard relic abundance is recovered. For weaker couplings, however, the partner decays after freeze-out and injects a non-thermal WIMP population, modifying the thermal history. This can lead to delayed freeze-out via re-annihilation or a subsequent freeze-in phase. In both regimes, achieving the observed relic abundance requires a larger WIMP annihilation cross section than in the standard scenario. As a result, current and upcoming indirect detection experiments can probe the partner’s mass and its coupling to WIMPs.

Speaker: Chance Hoskinson (University of Utah)

17:00 Accidentally Stable Dark Matter in a Parity Solution to the Strong CP Problem

Parity symmetry, with an extended gauge group $SU(3)_C\times SU(2)_L \times SU(2)_R\times U(1)_X$, can solve the strong CP problem. In particular, models where $SU(2)_R\times U(1)_X$ is broken by the Parity partner of the SM Higgs solves the strong CP problem without introducing extra symmetry. We discuss the possibility of accidentally stable dark matter in this framework and show that $SU(2)_L \times SU(2)_R$ bi-triplet fermions can be accidentally stable. We compute the relic abundance of the bi-triplet fermion and derive constraints on the parameter space from direct and indirect detection experiments.

Speaker: Matthew Baldwin

17:15 Reviving WIMP dark matter with temperature-dependent couplings

The persistent null results at dark matter (DM) direct-detection experiments have pushed the popular weakly interacting massive particle (WIMP) DM to tight corners. Generic WIMP models with direct-detection rate below the current upper limits often lead to a thermally overproduced relic abundance after freeze-out. To resolve this conundrum, we propose a novel scenario where DM has temperature-dependent couplings with the standard model (SM) bath. A scalar field having a large vacuum expectation value (VEV) at high temperatures generates sizeable DM-SM interactions leading to efficient DM annihilations responsible for generating the desired thermal relic. At lower temperatures, the scalar field VEV settles down to a small value as a result of a phase transition which can generically be of first order, effectively leading to suppressed DM-SM interaction rate at low temperature, consistent with null results at direct-detection experiments. Upper bound on thermal DM mass forces the first-order phase transition (FOPT) to occur at scales such that the corresponding gravitational wave signal remains within reach of future experiments like LISA.

Speaker: Dr Debasish Borah (Indian Institute of Technology Guwahati)

17:30 Freeze-in Dark Matter in Neutron Stars

Every neutron star is born in the process of core-collapse supernova explosion that, for a brief moment, reproduces conditions of the early Universe with temperatures $T\sim O(30\rm\,MeV)$. We calculate the production of Dark Matter $\chi$ from the SM particles in such events, SM $\to\chi\bar\chi$, for the freeze-in range of couplings, $\alpha_{\rm FI} \sim O(10^{-26}) $, finding that $O(10^{-6})$ $\chi$'s per nucleon is produced. The strong gravitational potential well of the neutron star retains a substantial fraction of these particles that will eventually undergo the reverse process of energy injection, $\chi\bar\chi\to$ SM. This abnormal energy injection may create observable signatures such as late-time heating of the neutron stars. To demonstrate the power of this method, we have constructed a set of simple dark matter models coupled to lepton currents, and showed that neutron stars provide unique constraints on parameter space that otherwise cannot be accessed by other means, probing effectively the scattering cross sections with the SM in the ballpark of $\sigma_{\chi\,\rm SM} \propto O(10^{-70})\,\rm cm^2$.

Speaker: Samya Roychowdhury (University of Minnesota)

17:45 Singlet Doublet Model Outside of Chemical Equilibrium

The singlet-doublet fermion model of dark matter is an economical weak-scale dark matter model, which realizes the dark matter abundance through interactions with the weak bosons of the Standard Model. Depending on the size of the Yukawa couplings in the model, the dark matter relic abundance can be realized via freeze-out (including co-annihilation), co-scattering, freeze-in, or a super WIMP mechanism. We analyze the ways this model can realize the dark matter density with particular emphasis on the regime where the Yukawa couplings in the model are small and chemical equilibrium among particles is not guaranteed. Future work includes generalizing this to the case where particles fall out of kinetic equilibrium and solving the full momentum-dependent Boltzmann equation is required.

Speaker: Alexander Takla (University of Michigan)

18:00 Questions on Fuzzy Dark Matter

While Cold Dark Matter (CDM) simulations predict divergent central density profiles (cusps), observations of dwarf galaxies reveal flat, constant-density cores. Fuzzy Dark Matter (FDM), composed of ultralight bosons, offers a potential solution through quantum pressure that opposes gravitational collapse, forming a stable cored ground state known as a soliton. However, standard FDM soliton models exhibit a scaling problem where heavier cores are predicted to be smaller, contrary to observational data suggesting heavier cores are larger. To resolve this fundamental discrepancy, this research explores the thermal evolution of FDM halos by treating them as ensembles of excited states within a grand canonical framework. Numerical results demonstrate a sharp phase transition from deep solitonic structures to shallower potentials at critical temperatures. Future challenges include defining appropriate ultraviolet cutoffs to regularize the partition function and deriving exact analytical formulas for the chemical potential and phase transition temperatures.

Speaker: Sunhaeng Hur (Virginia Tech)

18:15 Secluded effects on scalar light dark matter

In the continued search for dark matter (DM), community interest has extended beyond the standard Weakly Interacting Massive Particle paradigm to a richer set of possibilities. A major focus of upcoming DM searches involves light dark matter (LDM): a new class of candidates with masses on the MeV to GeV scale, characterized by a massive dark photon which mixes kinetically with the SM photon. LDM is often taken to readily interact with regular matter in the early Universe. This produces cosmological predictions for rates of DM interaction or production in today's experiments, with scalar candidates being particularly well-constrained. While the origin of the dark photon's mass is often left unspecified, we find that the inclusion of a dark Higgs as an explicit source of the associated symmetry breaking can significantly affect cosmological predictions for complex scalar DM. In particular, a light dark Higgs tends to shift predictions away from existing bounds, and in some scenarios beyond the reach of upcoming experiments. We present the effects of such a dark Higgs on detection prospects for accelerator-based and direct-detection experiments.

Speaker: Lilianna Hariasz (Simon Fraser University)

16:30 → 18:30 Electroweak: Session 2

16:30 The Whizard Monte Carlo and Top-Quark Physics

Whizard is a universal Monte-Carlo package for calculations and event generation at high-energy colliders. In this talk, I report on recent progress in NLO off-shell top-quark pair production at the LHC. Furthermore, I describe the present support and plans for top-quark and electroweak physics at future colliders such as FCC-ee, ILC/CLIC, or a high-energy muon collider.

Speaker: Wolfgang Kilian

16:45 Determination of the strong coupling constant from the recent CT25 parton distribution functions

We present a new determination of the strong coupling constant $\alpha_s(M_Z)$ from a global QCD analysis CT25 of parton distribution functions (PDFs) that incorporates high-precision experimental measurements from the Run-2 of the Large Hadron Collider together with a large sample of other measurements over a wide interval of energies. In addition to providing an up-to-date determination of $\alpha_s(M_Z)$ using NNLO calculations and a sensitive nucleon data set within a self-consistent framework, we critically assess the estimation of the uncertainty on $\alpha_s(M_Z)$ using some commonly used criteria, including the dynamical tolerance and Bayesian hierarchical models. Based on this in-depth examination of the CT25 global hadronic data set using a combination of analysis methods, we find $\alpha_s(M_Z) = 0.1183^{+ 0.0023}_{-0.0020}$ at the 68% credibility level.

Speaker: Kirtimaan Mohan (Michigan State University)

17:00 Interplay of $\alpha_s$, $m_t$ and gluon parametrization in CT PDF extractions

Achieving percent-level accuracy and precision in parton distribution functions (PDFs) requires a careful optimization of the theoretical and methodological ingredients entering their determination. In this talk, we present a multidimensional correlation study based on multiple CT25 PDF fits at NNLO in QCD, aimed at investigating and quantifying the correlations among the strong coupling $\alpha_s(M_z)$, the top-quark pole mass $m_t$, and the gluon PDF parameterization. We perform simultaneous fits using optimized combinations of recent high-precision differential cross-section measurements for top-quark pair production at the LHC, and illustrate the individual roles of the parameters contributing to the observed multidimensional correlations to understand their effect on the resulting PDFs. We then perform a simultaneous extraction of $\alpha_s(M_z)$ and $m_t$ and highlight their relation to the stability of the Higgs vacuum.

Speaker: Tanishq Sharma

17:15 Investigation of the difference in the angular distributions of Z to μμ events produced in quark-antiquark, guark-Gluon and Gluon-Gluon collisions

Modeling angular distributions of Z-decay leptons at the Large Hadron Collider (LHC) is important in precision electroweak measurements. Z production at the LHC is dominated by gluon processes and the quark-antiquark ($q \bar q$) process accounts for only $40\%$ of the cross section. We investigate the theoretical predictions (using the POWHEG-MiNNLOPS 2.0 event generator) for the difference in the angular distributions of $pp\to Z\to \mu \mu$ events produced via $q \bar q$, guark-Gluon ($qG$), and gluon-gluon ($GG$) processes. The simulation is done for a CMS-like detector for proton-proton collisions at the large hadron collider at $\sqrt{s}$=13 TeV. We investigate the angular coefficients $A_0$ and $A_2$ (for $\theta$ and $\phi$ distributions in the Collins-Soper frame) for the different processes and for different categories of events as a function of the $Z$ boson rapidity and transverse momentum ($P_T$). For the $q \bar q$ process $A_0^{ q\bar q }=P_T^2/(P_T^2+M^2)$ (where $M$ is the mass of the dilepton pair) is expected from purely geometrical considerations. For the $qG$ process $A_0$ is larger and dependent on patron distribution functions. Previous theoretical calculations find $A_0^{qG}\approx 5P_T^2/(5P_T^2+M^2)$. Our full simulation with the POWHEG-MiNNLOPS Monte Carlo (MC) indicates that this approximation is an overestimate. We show that the validity of this approximation can also be tested experimentally by measuring the angular coefficients for events with a single b-quark jet in the final state (which is primarily produced via the $qG$ process). In our simulation we also find that at 13 TeV the violation of the Lam-Tung (LT) relation $A_0=A_2$ is much smaller for events with only zero or one jet in the final state indicating that the violation of the LT relation originates from events with two or more jets in the final state. This can also be checked experimentally by measuring $A_0$ and $A_2$ for events with only zero or one jet in the final state.

Speaker: Giulia-Maria Bulugean (University of Rochester (US))

17:30 Precision Measurement of the Electroweak Mixing Angle in the Region of the Z pole

This contribution presents an overview of an improved extraction of the effective leptonic weak mixing angle, $\sin^2θ^ℓ_{eff}$, based on the published CMS measurement of the forward-backward asymmetry in Drell-Yan events at 13 TeV. While the original CMS analysis achieved a significant reduction in experimental uncertainties, its overall precision remains limited by residual uncertainties in the parton distribution functions (PDFs). This talk highlights the impact of incorporating complementary CMS measurements (W asymmetry and W/Z cross section ratio) that probe different combinations of parton densities, thereby providing additional PDF constraints beyond those obtained from the asymmetry measurement alone. The improved analysis leads to a substantially reduced total uncertainty, yielding $\sin^2θ^ℓ_{eff}$=0.23156±0.00024. This result is consistent with the Standard Model prediction and represents the most precise single determination of this parameter to date.

Speaker: Arie Bodek (University of Rochester (US))

17:45 Fermionic Electroweak Two-Loop Corrections to Drell-Yan and Related Processes

We perform a complete calculation of the next-to-next-to-leading order (NNLO) electroweak fermionic corrections to fermion-pair production processes. We do this via a semi-numerical technique that uses dispersion relations for the fermion sub-loop in two-loop box and vertex diagrams and dispersion relations and Feynman parameters for vertex diagrams with fermionic triangle sub-loops. We present numerical results for the cross-sections of $e^+e^-\to \mu^+\mu^-/u\bar{u}/d\bar{d}$ and differential distributions at representative center-of-mass energies. The NNLO corrections are found to modify the NLO cross-section on the order of 1%.

Speaker: Ernest Wallace (University of Pittsburgh)

18:00 Chasing 2HDM via electroweak corrections at e+e- colliders

In this talk, I will present a comprehensive study of Higgs boson production associated with a neutrino pair at 𝑒+𝑒− colliders (𝑒+𝑒−→ℎ𝜈𝜈¯) at NLO electroweak (EW) accuracy in both the SM and the two-Higgs-doublet model (2HDM). I will show that new physics effects from the extended Higgs sector can be probed through EW corrections, which lead to deviations from the SM predictions reaching 6% to 7%. Even in the alignment limit, these deviations can still reach 2% to 3%, making them experimentally testable. This highlights the potential of precision studies at future 𝑒+𝑒− colliders for searching new physics.

Speaker: Dr Yang Ma (UCLouvain)

18:15 Hadronic CP Violation in the 2HDM

We present the first complete two-loop calculation of the electric and chromo-electric dipole moments of the light quarks and the gluon, as well as contributions to CP-violating lepton-quark interactions, in the unconstrained two-Higgs doublet model. We include the most general Yukawa interactions of the Higgs doublets with the Standard Model fermions up to quadratic order, and allow for generic phases in the Higgs potential. We pay particular attention to a consistent treatment of all fermionic contributions in the low-energy effective theory, including a consistent renormalization-group summation of all leading-logarithmic effects. This latter part of the work is independent of the specific UV model and can generally be applied to a large class of models that do not introduce new light degrees of freedom. A python implementation of our results is provided via a public git repository.

Speaker: Daniil Volkov (University of Cinccinati)

16:30 → 18:30 Gravitational Waves

16:30 Gravitational Waves from an A4 Neutrino Mass Model

The $A_4$ flavor symmetry has provided tremendous insight into the flavor structure of the lepton sector of the Standard Model, predicting a very good approximation to neutrino mixing angles called tri-bimaximal mixing (TBM). $A_4$ is spontaneously broken by a scalar called the flavon, and when this happens a number of degenerate vacua can form, resulting in so-called domain walls. These objects are not observed and hence need to be annihilated. This is usually done by explicitly breaking $A_4$ by adding a bias term to the scalar potential. In this paper, we construct a new model invariant under $A_4 \times \mathbb{Z}_4$ which creates cosmologically viable domain walls, lifts the degeneracy of the vacuum giving a natural mechanism for domain walls to annihilate, as well as predicts realistic neutrino mixing angles; all utilizing cross couplings between flavons. The annihilation of the domain walls, with proper choice of wall tension and the consequent bias term, leads to a gravitational wave signal that is potentially detectable in near future gravitational wave experiments, and interestingly intersects with the observed Pulsar Timing Array signal.

Speaker: Cameron Moffett-Smith

16:45 Uncool phase transitions from soft walls

Theories with warped extra dimensions, like the Randall-Sundrum (RS) model, exhibit a holographic phase transition from a hot, deconfined black brane phase to a cool, confined phase. The standard picture of a first-order, strongly supercooled phase transition is expected to change in variations where the extra dimension is smoothly cut off by a soft-wall curvature singularity, as opposed to a hard brane. To understand this situation, we consider a simple ansatz for the warped geometry which allows us to obtain analytical results while maintaining the essential behavior of a soft wall. Unlike RS with the usual Goldberger-Wise stabilization, the hot, black brane phase only exists above a minimum temperature, which is not much smaller than the critical temperature. We explore the dynamics of the phase transition across the range of possibilities for the asymptotic geometry of a soft wall. The phase transition completes rapidly and with only slight supercooling. For a TeV-scale transition, the resulting gravitational wave signal is accessible to future space-based interferometers.

Speaker: Ameen Ismail

17:00 New Sensitivity to High Frequency Gravitational Waves from Radio Telescopes

Recently, there has been a wealth of new experimental proposals to potentially discover gravitational waves with frequencies in the MHz to GHz regime, which would be smoking-gun evidence of physics beyond the Standard Model. In this work, we show that existing radio telescope facilities like CHIME and FAST have comparable or better sensitivity to high-frequency gravitational waves than many proposed terrestrial experiments. These telescopes are sensitive to gravitational waves through the Gertsenshtein effect, a Standard-Model process by which gravitational waves convert to electromagnetic radiation in the presence of an external magnetic field. This conversion process would occur in the magnetic field of the Milky Way and solar system, causing the gravitational waves to appear as distinctive radio sources in the sky. Here, we demonstrate that radio telescopes have exceptional potential to discover primordial black hole mergers, the most realistic sources of high-frequency gravitational waves.

Speaker: Ethan Baker (Boston University)

17:15 Gravitational Waves from Early-Universe Turbulent sources

The early universe provides a natural testing ground for theories beyond the Standard Model. One well-motivated extension is the introduction of first-order phase transitions, which generically produce a stochastic gravitational wave (GW) background. In this work, we study GWs sourced by decaying turbulence and highlight the role of the relevant time scales, most notably the decay parameter and the turbulence duration, which govern distinct dynamical regimes of the system. Assuming the electroweak phase transition scale (~160 GeV), the resulting signal peaks in the LISA band (0.1 mHz – 1 Hz), while a QCD-scale transition (~100 MeV) would produce GWs in the nHz range (1–100 nHz), accessible to pulsar timing arrays. Upcoming observations can therefore constrain the relevant parameter space across complementary frequency bands.

Speaker: Murman Gurgenidze (Carnegie Mellon University)

17:30 Does NANOGrav favor massive gravity?

Pulsar timing arrays probe the stochastic gravitational wave background through the angular cross-correlations of pulsar timing residuals. For an isotropic tensor background in general relativity, the expected overlap reduction function is the Hellings-Downs curve. We investigate how ghost-free massive gravity modifies this prediction through a massive dispersion relation and additional vector and scalar polarizations. We correct previous treatments of the vector and scalar modes and show that in the general relativistic limit, their leading contributions scale as $(1 - A^2)^{-1}$ and $(1 - A^2)^{-2}$ respectively. This motivates a phenomenological screening of the non-tensor sectors to ensure that we recover the Hellings-Downs in the massless graviton limit. Using the NANOGrav 15-year dataset, we perform a Bayesian model selection scan over graviton masses $m_g \in [10^{-25},\,8.17\times10^{-24}]\,\mathrm{eV}$ and scalar suppression indices $n_S \in \{2,4,6,8\}$ with vector suppression index $n_V = 1$ fixed. Among the tested parameters, the largest preference over Hellings-Downs occurs for $m_g = 5.82\times 10^{-24}$ eV and $n_S = 2$, with a Bayes factor $\mathcal{B}\mathcal{F}_{10} \simeq 14.7$, indicating strong preference. These results show that PTA angular correlations provide a concrete phenomenological test of massive gravity.

Speaker: Chris Choi (Carnegie Mellon University)

17:45 Gravitational Waves from Long Strings and Loops

We compute the gravitational wave (GW) spectrum from scaling global cosmic string networks across infrared and ultraviolet scales. In the infrared (k ≲ ℓ^{-1}), we derive the spectrum analytically using the unequal time correlator (UETC) of the string stress-energy tensor within the unconnected segment and loop model (USLM), a new extension of the unconnected segment model that incorporates the loop contribution for the first time. In the ultraviolet (k ≳ ℓ^{-1}), we develop a data-driven method that connects the UETC formalism to the instantaneous radiation power spectrum measured in lattice simulations. We show that the loop contribution dominates over long strings at all observable frequencies. Confronting the predicted spectra with current and projected observational sensitivities, we derive new constraints on the symmetry-breaking scale fa and the axion mass ma.

Speaker: Christos Litos (University of Florida)

18:00 Testing Massive Gravity Using European Pulsar Timing Array Data

Pulsar timing array datasets are used to detect a stochastic gravitational wave background (SGWB) through angular cross-correlations between timing residuals measured from different pulsars. Analytically, these cross-correlations are computed through the overlap reduction function (ORF), which expresses the GW signal strength’s dependence on the angular separation of the pulsars. Since a GW’s characteristics are strongly model-dependent, the ORF takes different forms in modified models of gravity beyond general relativity. In our study, we focus on viable massive gravity (MG) in which the graviton has a tiny, non-zero mass. Such a theory of MG implies a modified dispersion relation and additional polarization modes for GWs. Accounting for these modifications of the SGWB, we compare the theoretically predicted ORFs with currently available observational data. In particular, we utilize the European Pulsar Timing Array Data Release 2 (EPTA DR2) to perform Bayesian analysis on the SGWB to determine if there is an observational preference for MG models.

Speaker: Marcus Bosca (Carnegie Mellon University)

18:15 Baryophilic gauge and Gravitational Wave Effect

We investigate a minimal extension of the standard model that includes an additional baryophilic abelian gauge symmetry. In these classically conformal models, the thermal phase transition, driven by the Coleman-Weinberg mechanism, is strongly first-order with significant supercooling, producing observable stochastic gravitational wave signals. Our analysis reveals a substantial parameter space within these models that can be probed by future gravitational wave observatories, such as LISA, BBO, DECIGO, and Cosmic Explorer.

Speaker: Mr Abdul Rahaman Shaikh (Centre for Theoretical Physics, Jamia Millia Islamia)

16:30 → 18:30 Neutrino Physics: Masses, Exp. Signatures

16:30 Sensitivity to Neutrino Mass and Secondary Physics of the Project 8 Experiment

Project 8 measures the electron-weighted neutrino mass by resolving the characteristic distortion caused by the nonzero neutrino mass on the tritium beta decay spectrum near its endpoint through Cyclotron Radiation Emission Spectroscopy (CRES). The Phase IV configuration, utilizing an atomic tritium source, is designed to achieve a sensitivity of 40 meV/c² (90% C.L.). Beyond this primary measurement, the exceptional energy resolution of Project 8 also enables other secondary physics searches, including light sterile neutrinos and cosmic relic neutrino capture, each of which induces distinct spectral signatures on the beta decay spectrum. This talk outlines the framework and key experimental parameters governing the sensitivity projections, and presents the physics reach of Project 8.

This work is supported by the US DOE Office of Nuclear Physics, the US NSF, the PRISMA+ Cluster of Excellence at the University of Mainz, and internal investments at all institutions.

Speaker: Chi-Ho Lam (University of Pittsburgh)

16:45 Direct Neutrino Mass Measurement with Project 8

Project 8 seeks to directly measure the electron-weighted neutrino mass using cyclotron radiation emission spectroscopy (CRES). Using this technique, the kinetic energy of magnetically-trapped $\beta$-electrons from tritium sources can be inferred by observing their cyclotron frequency, measuring the endpoint spectrum with high precision. Following the successful demonstration of CRES with waveguides, the upcoming phase of Project 8 will demonstrate the first realization of cavity-based CRES using Cavity CRES Apparatus (CCA) for enabling scalability to larger volumes. A cubic-meter scale apparatus called Low-Frequency Apparatus (LFA) is being designed to increase statistics and achieve sub-eV mass sensitivity, while also addressing remaining technical risks on the path to reaching the final sensitivity goal of 40 meV. This talk will give a brief overview of the Project 8 experiment, present recent advances in CCA instrumentation and the design progress of LFA.

This work is supported by the US DOE Office of Nuclear Physics, the US NSF, the PRISMA+ Cluster of Excellence at the University of Mainz, and internal investments at all institutions.

Speaker: Ehteshamul Karim (University of Pittsburgh)

17:00 Binary Neutron Star Mergers as a Probe of Neutrino Mass

Binary neutron star (BNS) mergers produce intense bursts of $\mathcal{O}(10)$ MeV neutrinos, but their low rate and typically large distances make detection extremely challenging. We revisit the prospects for observing the first neutrino from a BNS merger using updated merger rates and emission models, and find that detection is unlikely in current experiments, instead requiring next-generation megaton-scale detectors. While the basic idea of searching for merger neutrinos in coincidence with gravitational-wave events has been discussed in the literature, we include the time-of-flight delay from nonzero neutrino mass and show that it significantly modifies the optimal search strategy. In particular, we develop an efficient search strategy using energy-dependent timing windows and redshift cuts that can further improve the signal-to-background ratio. We determine the observation time required to detect a single BNS merger neutrino as a function of the upper bound on the lightest neutrino mass. Once detected, the relative timing of the neutrino and gravitational-wave signals can probe the neutrino mass scale, with sensitivity that can exceed both current KATRIN bounds and projected sensitivities from galactic supernovae.

Speaker: Dibya Sankar Chattopadhyay (Oklahoma State University)

17:15 Latest Results from the CUORE experiment

Neutrinoless double beta decay (0$\nu \beta \beta$) is a hypothesized lepton number violating process, the discovery of which would lead to a greater insight into the nature of neutrino mass. CUORE (Cryogenic Underground Observatory for Rare Events) is a bolometric search for 0$\nu \beta \beta$ in $^{130}$Te. The experiment employs TeO$_2$ crystals as both the possible sources and detectors of this decay. CUORE began data taking in 2017, and has obtained competitive limits on the effective neutrino mass since then. This talk will show the latest results from CUORE for 0$\nu \beta \beta$, as well as searches for other BSM signals.

Speaker: Vivek Sharma (University of Pittsburgh)

17:30 How long can neutrons live?

The neutron lifetime is a crucial parameter for many processes in nuclear and particle physics. However, existing experimental approaches, the beam and bottle methods, yield discrepant results. In this work, we propose a third, independent approach to determine the neutron lifetime. Our method is based on a novel experimental setup in which a modular reactor is placed near the XENONnT detector to measure the inverse beta decay cross section. This provides an alternative determination of the neutron lifetime that is independent of the existing techniques. We estimate the achievable experimental uncertainty and show that it is already approaching the level required to resolve the current tension. We further discuss possible improvements to the detector and setup that would enhance the sensitivity, with the goal of fully resolving the discrepancy and clarifying its origin.

Speaker: Yulun Li

17:45 Phenomenological Chiral Perturbation Theory for Neutrino Event Generators

The precise understanding of neutrino-nucleus interactions is essential for advancing the neutrino experimental program, particularly in the low-GeV energy regime relevant to current and future accelerator-based neutrino oscillation experiments such as DUNE, T2K, and Hyper-Kamiokande. In this energy regime, the nuclear response involves not only quasielastic scattering from individual nucleons but also significant contributions from inelastic channels such as resonance and pion production.

In this work, we employ chiral perturbation theory (ChiPT) to improve upon existing models of neutrino-nucleus cross sections by incorporating baryonic resonances in a theoretically consistent manner. ChiPT provides a systematic framework for describing low-energy interactions of pions and nucleons, including the production of resonances such as the Delta(1232). To complement Chiral Perturbation Theory (ChiPT), we adopt a phenomenological, data-driven approach to constrain the transition form factors.

The outcomes of this work are twofold. First, our work yields an accurate determination of single-pion and lepton production cross sections across a range of kinematics relevant to accelerator experiments. Second, we have developed a FeynRules implementation that encodes our ChiPT-based model in a format that is streamlined for use in the theory-driven Achilles event generator.

These results are accompanied by a software package that makes our model accessible to the broader neutrino community, facilitating its integration into experimental analyses and enabling more precise assessments of cross-section uncertainties.

Speaker: Misa Toman

18:00 Form Factor Uncertainty Analysis for Coherent Neutrino Trident Scattering

We present the first detailed analysis of nuclear form factor uncertainties relevant for neutrino trident processes. We focus on argon charged form factors given their relevance in current and next-generation neutrino experiments. Accurately quantifying this uncertainty is important to perform precision Standard Model physics analyses and Beyond the Standard Model searches using neutrino tridents, a feat which will be possible for the first time with these experiments. Previously, such uncertainties were estimated to be $\sim 1\%$. Our work shows that uncertainties can be as high as $\sim 10\%$ for argon depending on the choice of parametrization, leading to a $\mathcal{O}(100)$ variation in the number of expected trident events at the DUNE experiment.

Speaker: Diego Lopez Gutierrez (Washington University in St Louis)

18:15 Global Extraction of the Nuclear Electromagnetic Response Functions of C-12 and Comparisons to the Predictions of the SuSAv2 Superscaling Formalism for Electron and Neutrino Scattering

We perform a global extraction of the ${\rm ^{12}C}$ longitudinal (${\cal R}_L$) and transverse (${\cal R}_T$) nuclear electromagnetic response functions from an analysis of all available electron scattering data on carbon. The response functions are extracted for energy transfer $\nu$, spanning the nuclear excitation, quasielastic (QE), resonance and inelastic continuum over a large range of the square of the four-momentum transfer, $Q^2.$ In addition, we perform a universal fit to all ${\rm ^{12}C}$ electron scattering data which also provides parmeterizations of ${\cal R}_L$ and ${\cal R}_T$ over a larger kinematic range. Given the nuclear physics common to both electron and neutrino scattering from nuclei, extracted response functions from electron scattering spanning a large range of $Q^2$ and $\nu$ also provide a powerful tool for validation and tuning of neutrino Monte Carlo (MC) generators. In particular, the predictions of the SuSAv2 formalism (which is implemented in the GENIE electron and neutrino scattering generator) are in disagreement with the electron scattering data. We extract $Q^2$ dependent correction factors to the SuSAv2-QE and SuSAv2-MEC-2p2h predictions for ${\cal R}_T$ and ${\cal R}_T$ to the theory for better agreement with electron scattering data.

Speaker: Zihao Lin (University of Rochester)

Tuesday 12 May

08:00 → 08:40 Breakfast

08:40 → 10:30 Plenary: Tuesday Early

Convener: Lisa Everett

08:40 APS & its Journals

Speaker: Joshua Sayre

08:45 Highlights of the Recent LHC Results

09:20 HL-LHC and Future Perspectives

Speaker: Sarah Marie Demers (Yale University (US))

09:55 Precision Physics in the LHC Era

Speaker: Federico Buccioni (University of Zurich)

10:30 → 11:00 Coffee Break

11:00 → 12:45 Plenary: Tuesday Late

Convener: Kaladi Babu

11:00 Flavor Physics in the New Era

Speaker: Zoltan Ligeti (Lawrence Berkeley National Lab. (US))

11:35 New Directions in Collider Physics

Speaker: Zhen Liu

12:10 Quantum Information Meets Collider Physics

Speaker: Fabio Maltoni (Universite Catholique de Louvain (BE))

12:45 → 14:00 Lunch Break

14:00 → 16:00 Computing and Machine Learning

14:00 Mini Review: Deep Learning in HEP

Speaker: Sergei Gleyzer (University of Alabama (US))

14:30 Memristive tabular variational autoencoder for compression of analog data in high energy physics

We present an implementation of edge AI to compress data on an in-memory analog content-addressable memory (ACAM) device. A variational autoencoder is trained on a simulated sample of energy measurements from incident high-energy electrons on a generic three-layer scintillator-based calorimeter. The encoding part is distilled into tabular format by regressing the latent space variables using decision trees, which is then programmed on a memristor-based ACAM. In real-time, the ACAM compresses 48 continuously valued incoming energies measured by the calorimeter sensors into the latent space, achieving a compression factor of 12x, which is transmitted off-detector for decompression. The talk is based on our preprint (arXiv:2602.15990).

Speaker: Tae Min Hong (University of Pittsburgh (US))

14:45 Many Wrongs Make a Right: Leveraging Biased Simulations Towards Unbiased Parameter Inference

In particle physics, as in many areas of science, parameter inference relies on simulations to bridge the gap between theory and experiment. Recent developments in simulation-based inference have boosted the sensitivity of analyses; however, biases induced by simulation-data mismodeling can be difficult to control within standard inference pipelines. In this talk, we propose a Template-Adapted Mixture Model to confront this problem in the context of signal fraction estimation: inferring the population proportion of signal in a mixed sample of signal and background, both of which follow arbitrarily complex distributions. We harness many biased simulations to perform data-driven estimates of each process distribution in the signal region, substantially reducing the bias on the signal fraction due to the domain shift between simulation and reality. We explore different methodological choices, including model selection, feature representation, and statistical method, and apply them to a Gaussian toy example and to a semi-realistic di-Higgs measurement. We find that the presented methods successfully leverage the biased simulations to provide estimates with well-calibrated uncertainties.

Speaker: Sean Benevedes (Massachusetts Institute of Technology)

15:00 Toward Agentic Phenomenology

Frontier LLMs have transformed from text generators into programmable agents, opening a new paradigm for scientific computing. I will discuss HEPTAPOD, a HEP-focused agentic toolkit that interfaces LLMs with common numerical and symbolic workflows. I'll illustrate the framework on some standard benchmarks. To close, I'll turn to a broader discussion of agentic programming, the range of applicability of LLM agents in HEP, and the road towards autonomous agency.

Speaker: Tony Menzo (University of Alabama and Fermilab)

15:15 Binning Bonanza: Metric Design for Quantum Observables and Efficient Dimensionality Reduction

Modern particle physics measurements increasingly rely on precise characterizations of subtle quantum effects, making the identification of optimal observables a significant challenge. We present a framework that defines a new metric for evaluating the performance of observables sensitive to quantum interference. We also demonstrate how most of the relevant multidimensional information to separate any given hypotheses can be effectively stored in a small number of bins, allowing for efficient data analysis, data preservation, and global data combination, while providing the tools to do so in the MiLoMerge package for Python. A key feature of this approach is the reduction in the dimensionality of observable information, which enhances both the effectiveness and practicality of the data analysis while maximizing gains within limited resources. These features have been demonstrated through simulated analyses of Higgs boson production and decay processes at the LHC.

Speaker: Mohit Vir Srivastav (Johns Hopkins University (US))

15:30 Generative quantum machine learning for the hadronization process

Phenomenological studies at particle colliders rely on high-fidelity simulation data. These simulations are typically produced using Monte Carlo event generators such as Pythia and Herwig. However, several components of the event-generation pipeline, most notably hadronization, are sensitive to nonperturbative quantum chromodynamics (QCD), where first-principles understanding is limited. As a result, traditional event generators depend on phenomenological hadronization models whose parameters are tuned to experimental data, potentially introducing systematic uncertainties and causing deviations from experimental measurements. Recent advances in classical machine learning have begun to explore data-driven approaches to hadronization using generative models, which offer greater flexibility than traditional parameterized models and may thus improve simulation accuracy. Because hadronization is fundamentally a quantum process, quantum machine learning may provide a particularly natural framework for modeling its underlying structure. Motivated by this possibility, we present a proof-of-concept study of generative quantum machine learning applied to hadronization.

Speaker: Jinghong Yang

15:45 -

14:00 → 16:00 Cosmology: CMB, GW

14:00 Echoes of global cosmic strings

Spontaneous symmetry breaking of global symmetries in the early universe may leave behind topological defects known as cosmic strings. These strings continuously emit the symmetry’s pseudo Nambu-Goldstone boson, which contributes to the dark matter density after it becomes non-relativistic. In the talk, I will discuss the numerical and analytical methods we developed to evaluate the density power spectrum induced by these relics and present the constraints on their mass and symmetry breaking scale, derived by comparison with various cosmological observables.

Speaker: Antonios Kyriazis (University of Florida)

14:15 Spectator Composes Gravitational Canon

We propose a general framework in which a phase transition is triggered during cosmic inflation by the slow-roll dynamics of a spectator field. The topological defects formed at the transition are inflated outside the horizon, reenter it after inflation, and can subsequently generate characteristic gravitational-wave (GW) signals. Quantum fluctuations of the spectator field modulate the timing of the transition, imprinting large-scale anisotropies in the resulting GW background. As an explicit realization, the spectator field may be identified with the Higgs field in a supersymmetric Standard Model. More generally, our framework applies to a wide class of spectator-modulated phenomena, providing a generic mechanism for producing anisotropic GW signals.

Speaker: Yunjia Bao (University of Chicago)

14:30 Kinetic Isocurvature Perturbations

In this talk, I will formulate a new class of primordial perturbations called kinetic isocurvature perturbations, where the mass density of dark matter is constant relative to the photon number density while the kinetic energy of dark matter fluctuates in space. Such perturbations naturally arise in scenarios where a nonrelativistic heavy field decays into relativistic dark matter particles with a spatially modulated rate. As dark matter cools and becomes nonrelativistic, these fluctuations in kinetic energy leave large-scale density perturbations essentially unaffected and therefore evade the Cosmic Microwave Background bounds on isocurvature perturbations, yet survive as spatial variations in the free-streaming scale, resulting in patch-by-patch variation of the matter power spectrum.

Speaker: Dhong Yeon Cheong (University of Chicago)

14:45 Primordial Features and Their Impact on Structure Formation

The dynamics of the early universe has the possibility to imprint interesting features on the spectrum of primordial perturbations which serve as initial conditions for the standard hot big bang evolution and formation of structure at later times. In the inflationary paradigm, sharp features in the trajectory of the inflaton could lead to interesting deviations away from the standard nearly-scale-invariant primordial spectrum, in turn imprinting on cosmological observations. In this talk, I will focus on the impact that features in the primordial spectrum have on the formation of structure in the late universe. I will outline the classes of models that may cause these phenomena and describe the expected effects on the distribution of dark matter haloes at late times by computing the halo mass function. I will also briefly compare these scenarios to other phenomena which may have similar impacts on structure formation, such as first order phase transitions in the early universe.

Speaker: Dr Itamar Allali (Brown University)

15:00 Current and Future Constraints on the Primordial Power Spectrum

Many models of inflation and the early universe provide specific predictions for the values of the scalar spectral index $n_s$ and its running, $\alpha_s$. Considering current data from ACT DR6, Planck, SPT-3G DR1, and DESI DR2 it was found that key models of inflation, including the Starobinsky model, were ruled out at $2\sigma$. However we find that when additionally varying the number of light relativistic species (i.e. $N_\mathrm{eff}$), these models are no longer ruled out. We also find that future CMB experiments such as the Simons Observatory and CMB-HD would be able to rule out these inflation models with high confidence, even when varying these additional degenerate parameters. We validate our forecasts using both CAMB and CLASS, finding agreement in forecasted parameter errors to within 6% and spectra within 0.5% for multipoles up to $\ell = 20000$.

Speaker: Zachary Cheslog (Stony Brook University)

15:15 A Step in Flux to Suppress Axion Isocurvature

The QCD axion in the pre-inflation scenario faces a stringent isocurvature constraint, which requires a relatively low Hubble scale during inflation. If the axion was heavier than the Hubble scale during inflation, its isocurvature is suppressed and the constraint disappears. We point out a novel mechanism for achieving this, relying on the topological nature of a BF-type (monodromy) mass for the axion. Such a mass term has an integer coefficient, so it could naturally have been very large during inflation and exactly zero by the time of the QCD phase transition. This integer can be viewed as a quantized flux, which is discharged in a first-order phase transition that proceeds by the nucleation of charged branes. This mechanism can be embedded in cosmology in several different ways, with tunneling during, at the end of, or after inflation.

Speaker: Zekai Wang (Harvard univeristy)

15:30 Cosmological Signals from Finite-Lifetime Domain Wall Networks

We study cosmological perturbations sourced by a domain wall (DW) network with a finite lifetime. Allowing DWs to decay avoids the stringent CMB energy density constraints, enabling signals that are relevant for both the CMB and measurements sensitive to smaller scales (higher $k$-modes). Using the uncorrelated segment model (USM) to describe the DW energy-momentum tensor, we derive analytical expressions for the scalar and tensor power spectra and clarify their $k$-dependence. In contrast to the first-order phase transition (FOPT) that reheats into dark radiation, DW-induced superhorizon perturbations continue to grow on scales larger than the PT horizon, and only transition to a $k^{3}$ scaling for modes entering the horizon after DW collapse. By comparing with existing curvature perturbation constraints, we determine the maximal $B$-mode signal from DW-sourced tensor perturbations, which can easily exceed the inflationary signal with $r=10^{-3}$.

Speaker: Fengwei Yang (University of Notre Dame)

15:45 First Search for Kaluza-Klein Gravitons and Radion Using Planck Data

Compact extra dimensions appear in various scenarios beyond the Standard Model (SM) of physics, including string theory, but their experimental signatures have not been observed yet. If the energy scale associated with extra dimensions is too high, then the signatures will not be observable in terrestrial colliders. The cosmological period of inflation, however, is an epoch where the energies are high enough for extra-dimensional signatures to be relevant. For example, the production of on-shell Kaluza-Klein (KK) gravitons and radions during inflation could give rise to three-point functions (bispectrum) of density perturbations within the cosmological collider (CC) scenario. We compute the full shape of the bispectrum mediated by the KK gravitons and the radion for the first time, utilizing the Randall-Sundrum model. We then search for the bispectra shapes in the Planck 2018 data. We also comment on the overlap of our results with those of a generic massive spin-2 particle in the usual effective field theory of inflation, as well as comment on the usage of the cosmological bootstrap technique.

Speaker: Alexander Cassem (Tufts University)

14:00 → 16:00 Dark Matter: Axions

14:00 Berry Phase in Axion Physics and Its Applications

We investigate the Berry phase arising from axion-photon and axion-fermion interactions. The effective Hamiltonians in both systems share the same form, enabling a unified description of the Berry phase and offering an alternative viewpoint on current axion experiments. We conceptually propose a new photon-ring experiment for axion detection. Furthermore, we demonstrate that measuring the axion-induced Berry phase offers a method for probing the global structure of the Standard Model gauge group and axion-related generalized symmetries.

Speaker: Shuailiang Ge (KAIST & UChicago)

14:15 WIMP Meets ALP: Coherent Freeze-Out of Dark Matter

The microscopic nature of dark matter is the major open question in science. Weakly Interacting Massive Particles (WIMPs) and Axion-Like Particles (ALPs) are the two most theoretically motivated dark matter candidates. Thousands of papers consider them separately. We point out that if both species are present in the theory, even a tiny (Planck-suppressed) interaction between them can lead to drastic modifications of their dynamics in the early Universe. This can dramatically change predicted properties of WIMP and ALP dark matter particles, such as their masses and annihilation cross sections. This in turn leads to important consequences for experiments searching for particle dark matter.

The talk is based on our recent work: https://arxiv.org/pdf/2511.16731.

Speaker: Bingrong Yu (Cornell University)

14:30 Geo-Axion Searches in Neutrino Detectors

The Earth may provide an interesting source both for the production and detection of axions. The crust and mantle portion contain heavy radionuclides, which can produce axions either via nuclear transitions or Primakoff scattering. We look at the detection capabilities of large scale neutrino detectors like DUNE, JUNO, etc. in probing the axion-nucleus coupling $g_{aNN}$ as well as the axion-photon coupling $g_{a\gamma}$.

Speaker: Anirudh Chandra Shekar (Texas A&M University)

14:45 The Challenges of Detecting Non-Classical Axions

Despite the possibility of the axion field being in a non-classical state, observing its intrinsically quantum features in a realistic detector is prohibitively difficult. I will discuss the necessary formalism to calculate potentially non-classical statistics of a quantum continuous measurement record, and I will demonstrate the two leading effects that wash out the non-classical statistics: a realistic detector's coarse graining over many axion field modes, and severe suppression of these statistics by increasing powers of the detection efficiency.

Speaker: Joseph Takach (UC Berkeley)

15:00 Axion Production and Detection Using a Dual NMR-type Experiment

Axions that couple to nuclear spins via the axial current interaction can be both produced and detected using nuclear magnetic resonance (NMR) techniques. In this scheme, nuclei driven by a real oscillating magnetic field in one device act as an axion source, which can drive NMR in a nearby spin-polarized sample interrogated with a sensitive magnetometer. We study the prospects for detecting axions through this method and identify two key characteristics that result in compelling detection sensitivity. First, the gradient of the generated axion field can be substantial, set by the inverse distance from the source. Near the source, it reduces to the inverse of the source’s geometric size. Second, because the generated axion field is produced at a known frequency, the detection medium can be tuned precisely to this frequency, enabling long interrogation times. We show that the experimental sensitivity of a pair of centimeter-scale NMR devices operating over a 15-day integration time can already surpass existing astrophysical bounds on the axion-nucleon coupling. A similar sensitivity can be achieved with 10 centimeter-scale NMR devices with only 1 hour of integration time. These dual NMR configurations are capable of probing a wide range of axion masses, up to values comparable to the inverse distance between the source and the sensor.

Speaker: Qiushi Wei (University of Florida)

15:15 Cosmic Axion Background Detection Using Resonant Cavity Arrays

Relativistic axions produced in the early universe can form a Cosmic axion Background (C$a$B), providing a target that is distinct from conventional cold axion dark matter. In this talk, I will present a framework for searching for the C$a$B using arrays of resonant cavities in a strong magnetic field as in the future ADMX project. Although the C$a$B is broadband and has a much shorter coherence length than cold dark matter, a high-$Q$ cavity filters the axion field into a narrow-band electromagnetic response whose spatial correlations can be exploited across multiple detectors. I derive the axion-induced electric-field two-point correlation function for multi-cavity arrays and show that sensitivity depends non-trivially on cavity aspect ratio and array layout. In particular, I find that ADMX's prospective arrays suffer a relativistic suppression, while a new vertically stacked fat-cavity array provides a more improved sensitivity. These results illustrate how detector geometry and inter-cavity correlations can open a new avenue for probing relativistic axion backgrounds.

Speaker: Soobeom Chung (University of Florida)

15:30 Quantum Semiconductor Heterostructures for meV Axion Dark Matter Detection

We propose a novel strategy and a new class of detectors for the direct detection of axion dark matter in the meV mass range, based on resonantly enhanced axion–photon conversion through the inverse Primakoff effect in engineered radiometers composed of quantum semiconductor heterostructures. Semiconductor-Quantum-Well Axion Radiometer Experiments (SQWARE) are multiple quantum well structures forming magnetoplasmonic cavities, containing high-mobility two dimensional electron gases, realizing tunable epsilon-near-zero resonances in the terahertz frequency range. By controlling the orientation of the cavity within a strong external magnetic field, both the resonance frequency and the axion-induced current are optimized in situ, enabling efficient scanning across a broad mass range without the need for complex mechanical adjustments. The axion-induced electromagnetic signal radiatively emitted from the cavity is then detected by a photodetector. We present the theoretical basis for resonant enhancement, detail the experimental design and benchmarks through extensive simulations, project the sensitivity of an example SQWARE for several realistic configurations, and demonstrate the modularity and flexibility of the design to fit reasonably with any lab’s existing capabilities and target unique axion mass ranges. Our results demonstrate that SQWARE can probe the well-motivated quantum chromodynamics axion parameter space and close a critical gap in direct searches at meV masses.

Speaker: Jaanita Mehrani

15:45 Learning Loss Functions

We perform the highest-throughput search and evaluation of inorganic materials that can serve as excellent low-mass dark matter detectors. We use a graphical neural network (GNN) based on the GNNOpt architecture to learn and generate dielectric tensors, loss functions and sensitivity curves for both isotropic and anisotropic materials. Since the only required input for this GNN model is the structure of the unit cell, this analysis can now be expanded to any known inorganic material, increasing the number of materials analyzed by over 2 orders of magnitude. We apply this model to all materials available on the Materials Project database and show the results for absorption and scattering between dark matter and electrons. We also extend the GNN to predict anisotropy in the materials and calculate daily modulation in the interaction rates, which enables sensitivity to the dark matter wind. The training dataset is derived from nearly one thousand DFT-calculated dielectric tensors taken from Materials Project as well as previously calculated loss functions and sensitivity curves. The GNN predicts the output to percent level accuracy with no prior knowledge of DFT and the output obeys the Kramers-Kronig relations and physical sum rules similarly to the original dataset.

Speaker: Bethany Suter (UC Berkeley)

14:00 → 16:00 Electroweak: Spin and QM

14:00 Quantum Observables and Higher-Order effects in Leptonic $h \to VV^*$ Decays

Angular correlations in Higgs decays to electroweak gauge bosons, $h \to ZZ^*,WW^*$, provide a powerful probe of both new physics effects and quantum information observables. At leading order, the system admits an effective two-qutrit description, yielding entangled states across the entire kinematic spectrum. We show that next-to-leading order electroweak corrections introduce significant modifications to the angular observables that challenge the two-qutrit interpretation in the $h \to e^+e^-\mu^+\mu^-$ channel, while the $h \to WW^*$ channel remains comparatively robust.

Speaker: Dorival Gonçalves (Oklahoma State University)

14:15 Higher-order corrections to quantum observables in semileptonic Higgs decays

We present a systematic study of semi-leptonic decays $h \to V V^* \to \ell^+\ell^- q\bar{q}$ and $\ell^\pm \nu_\ell q\bar{q}'$, including finite final state fermion masses, NLO QCD, and NLO electroweak corrections. We show that finite final state quark masses can induce effects that go beyond the two-qutrit description in more inclusive regimes, while remaining controllable with suitable kinematic selections. QCD corrections lead to modest percent-level shifts, whereas electroweak corrections can significantly modify the angular structure, particularly in the $h\to ZZ^*$ channels. We assess the impact of these effects on the reconstructed density matrix and entanglement measures, finding that, while they modify the angular observables, semi-leptonic channels retain an effective two-qutrit description.

Speaker: Alberto Navarro (Oklahoma State University)

14:30 Study of spin correlations in Higgs boson decays to four leptons at CMS

Spin correlations in the Higgs boson decay to four leptons are investigated through detailed studies of kinematic distributions, using matrix element techniques to maximize sensitivity to the tensor structure of the Higgs boson interactions. The analysis, based on data collected by the CMS experiment at the LHC, probes the full decay dynamics, including quantum mechanical interference effects arising from permutations of identical leptons. The polarization density matrix in the H -> ZZ channel is measured, enabling tests of quantum entanglement with implications for violation of a Bell-type inequality. Within this framework, a simultaneous determination of eight Higgs boson couplings to electroweak vector bosons is performed using effective field theory, providing a comprehensive characterization of possible deviations from the Standard Model.

Speaker: Nicholas Pinto (Johns Hopkins University (US))

14:45 Spin‑Density Matrices as probes of CP violation in Top–Higgs Interactions

We investigate how CP‑violating top–Higgs couplings could influence top‑quark pair production at the LHC. To study these effects, we construct the reduced spin density matrix of the $t \bar{t}$ final state and explore a broad class of observables, including those motivated by quantum‑information approaches to spin correlations. We make use of an automated framework that provides the reduced helicity density matrix for $gg,q\bar q \rightarrow t \bar t$ while incorporating the effects of both QCD and electroweak corrections. The phenomenological model we employ requires a careful treatment of renormalization in the on‑shell scheme. This setup offers a flexible platform for assessing how CP‑violating Yukawa structures manifest in the spin and correlation patterns of the top–antitop system and for exploring the potential of quantum‑information–motivated observables in hadronic environments.

Speaker: Marcel I. Yanez

15:00 Decoherence or Recoherence in the Radiative Decay of Z boson

Final state hard radiation of photons or gluons is a critical NLO phenomena to consider at high energy colliders since it can change the kinematics and physics probed. In the maturing field of quantum information at colliders there has been an increased interest in investigating the effect of radiation on the bipartite spin entanglement of fermion pairs. Within this quantum information framework, the final state radiation can be seen as interaction with environmental degrees of freedom leading to decoherence of the fermion pair. We study the radiative decay of the Z boson: $Z \rightarrow \tau^- \tau^+ \gamma$ as an illustrative example for exploring decoherence. We consider the complete 3-body kinematics and explore various quantum information observables to quantify the decoherence effect on the tau pair bipartite system. Interestingly, we find hard photon radiation does not always reduce the fermion pairs’ entanglement and there even exists phase space where the photon can increase the entanglement of the fermions.

Speaker: Harman Singh (University of Pittsburgh)

15:15 NLO EW Corrections and Spin Observables for $\gamma\gamma \to \tau^+\tau^-$ in Pb-Pb UPCs

We study the $\gamma\gamma \to \tau^+\tau^-$ process in Pb--Pb ultraperipheral collisions, including the full spin information of the $\tau^+\tau^-$ system. We present predictions for the corresponding cross sections and spin correlations at next-to-leading-order electroweak accuracy, and find that the electroweak correction increases the total cross section by about nine per mille at the benchmark center-of-mass energies $\sqrt{s_{NN}}=5.02$, $5.36$, and $5.52~\mathrm{TeV}$, while its impact on the spin-correlation observables considered here is numerically small. In addition, we use the predicted spin correlations to investigate quantum entanglement in the $\tau^+\tau^-$ system produced in the $\gamma\gamma \to \tau^+\tau^-$ process. Our results indicate the presence of a genuinely entangled configuration near the $\tau^+\tau^-$ invariant-mass threshold.

Speaker: Peng-Cheng Lu (Shandong university)

15:30 Quantum Tomography of Fermion Pairs in $e^+e^-$ Collisions: Longitudinal Beam Polarization Effects

We present a quantum tomography study of fermion pair production at future $e^+e^-$ colliders, emphasizing how longitudinal beam polarization controls the two-qubit spin density matrix. We study the processes $e^+ e^- \to t\bar{t},\ e^+e^-\to \mu^+\mu^-$ and Bhabha scattering $e^+e^-\to e^+e^-$, representing the mass threshold behavior, the $Z$ pole resonance and the $s/t$-channel interplay. We choose to focus on three key concepts: quantum entanglement via the concurrence $\mathcal{C}$, Bell nonlocality via the optimal Clauser Horne Shimony Holt (CHSH) parameter $\mathcal{B}$, and non-stabilizerness (''magic'') via the second stabilizer Renyi entropy $\mathcal{M}_2$. For the $s$-channel-dominated channels, longitudinal polarization mainly reshapes single-spin polarizations while leaving the spin-correlation matrix largely unchanged, rendering $\mathcal{C}$ and $\mathcal{B}$ comparatively robust, but inducing a pronounced variation of $\mathcal{M}_2$. In contrast, in Bhabha scattering, polarization modifies the relative contributions of the $s$-channel and $t$-channel and can strongly affect all three observables. The observability of entanglement, Bell nonlocality, and magic exceeds the $5\sigma$ level when both statistical and systematic uncertainties are included, establishing the fermion pair systems as ideal laboratories for quantum-information studies in high energy leptonic collisions. With optimized beam polarization, future $e^+e^-$ colliders will provide a unique opportunity to experimentally explore and influence quantum resources in particle interactions.

Speaker: Youle Su (University of Pittsburgh)

15:45 Leggett-Garg Inequality Violation with Muon g-2 Experiments

Sometimes referred to as the temporal Bell inequality, the Leggett-Garg inequality (LGI) is a statement about correlations among measurements of a system at different times. Previously studied in quantum-mechanical systems such as neutrino oscillations, the spin precession of the muon at muon g-2 experiments provides a new pathway for measuring the LGI. In this talk I’ll discuss steps for constructing the LGI in this scenario and show its violation due to the muon’s spin precession.

Speaker: Morgan Cassidy

14:00 → 16:00 Neutrino Physics: Session 2

14:00 Neutrino/Beam-Dump Complementarity for New Physics

Novel search strategies are constantly being proposed for new-physics discovery at neutrino facilities -- this is driven in part by the enormous amount of data soon to be at hand. Many of these searches have great complementarity to other approaches, for instance the long-standing beam-dump strategy to search for new particles in rare events. In this talk, I will show some new techniques and highlight how neutrino and beam-dump facilities can work hand-in-hand to better our chances of discovery in the next decade.

Speaker: Kevin Kelly (Texas A&M University)

14:15 Widen the Resonance: Probing a New Regime of Neutrino Self-Interactions with Cosmic Neutrinos

Neutrino self-interactions beyond the Standard Model are well motivated by nonzero neutrino masses. We explore a scenario in which the lightest neutrino species remains relativistic today, leading to a broadened “widened” resonance in neutrino scattering that enhances sensitivity to new physics. This effect enables probes of neutrino self-interactions across a wide mediator mass range: (1) Hyper-Kamiokande observations of the diffuse supernova neutrino background can reach sub-keV mediators with couplings as small as g∼1e-8 (2501.07624 PRL); (2) ultra-high-energy neutrino experiments such as GRAND can test MeV–GeV mediators down to g~1e-3 (2512.00165). This unified framework opens new opportunities to probe neutrino properties and their connections to the dark sector across multiple energy scales.

Speaker: Bei Zhou (Fermilab)

14:30 Charged Lepton Flavor Violation at Neutrino Telescopes

Lepton flavor violation in neutrinos aka neutrino-oscillation is a telltale signature of Beyond the Standard Model (BSM) physics. If a similar phenomenon is found in the charged leptons as well, that will further consolidate the existence of BSM physics. In this work, we look for signature of charged lepton flavor violation (CLFV), muon to tau conversion, in the IceCube. We focus on two main scenarios: (a) CLFV interactions described by Effective Field Theory (EFT) operators and (b) the BSM mediator of such charged lepton flavor violating interaction being an axial-vector $Z'$. We set a constraint on the relevant new physics energy scale of the EFT operators and on the parameter space of $Z'$ from the analysis of the existing IceCube data. We compare our obtained constraint to that from collider experiments as well. Moreover, we predict a plausible constraint from two specific future generation experiments, IceCube-Gen2 and HUNT.

Speaker: Writasree Maitra (Department of Physics, Washington University in St. Louis)

14:45 Testing RG Evolution of Neutrino Mixing with IceCube Double Bang Events

Neutrino oscillation parameters are subject to renormalization group (RG) evolution, just like all couplings and masses of Standard Model (SM) particles. Within the SM extended with three massive neutrinos, it is well known that RG running effects in the neutrino sector are small. However, the RG running of the elements of the leptonic mixing (PMNS) matrix below the electroweak symmetry breaking scale can be enhanced in the presence of light neutrinophilic new particles. In this talk, using a particular low-scale neutrino mass model as an example, I will show that RG running of the PMNS matrix can lead to an increased number of high-energy tau neutrino events in the atmospheric and astrophysical neutrino fluxes at IceCube. This excess manifests as an increased number of spatially displaced showers called ‘double bangs’. The number of double bangs induced by new physics through RG effects can be comparable to that arising from SM interactions of astrophysical tau neutrinos.

Speaker: Mr Samiur R. Mir (Oklahoma State University)

15:00 Constraining hyperons and non-standard interactions with anti-electron neutrinos

The novel forward neutrino program at the Large Hadron Collider offers a new handle for understanding forward hadron production in pp collisions, inferred from neutrino interactions in a forward detector. Most existing and proposed high energy neutrino experiments have excellent muon charge identification capabilities, enabling the distinction of $\nu_\mu$ and $\bar \nu_\mu$ charged current interactions. In contrast, distinguishing electrons and positrons from $\nu_e$ and $\bar \nu_e$ interactions is typically impossible, as they interact quickly within dense detector materials and do not reach the spectrometer. We propose a compact and cost-effective plastic target, placed right before the spectrometer, to maximize the rate of electrons and positrons reaching the spectrometer before interacting. When installed at the FASER or FASER2 experiments, the setup enables the first separate measurement of $\nu_e$ and $\bar\nu_e$ cross sections at high energy, and constraining forward $\Lambda$ hyperons. This reduces flux uncertainties, thereby improving limits on non-standard neutrino interactions in neutral currents.

Speaker: Dr Toni Makela (University of California, Irvine)

15:15 Drell-Yan Production of New Particles at Fixed-Target Experiments: Heavy Neutral Lepton as a Case Study

We demonstrate the sensitivity of Drell-Yan production processes from deep inelastic scattering in searches for beyond-the-Standard Model (BSM) physics at fixed-target or beam-dump experiments. We take heavy neutral leptons (HNLs) as a case study, produced from the decay of a light vector boson mediator with mass in the range of 2 - 20 GeV, which itself is generated via the Drell-Yan process. The produced HNLs subsequently decay into Standard Model final states. We consider several current and future experiments, including SBND, DarkQuest, DUNE Near Detector (ND), and SHiP. Utilizing $\nu \pi^0$ and $\nu  e^+ e^-$ final states from HNL decays, we find that the Drell-Yan mechanism provides important contributions and significantly enhances the HNL search sensitivity, owing to the production of energetic final-state particles that are more readily detectable over the expected backgrounds. Our approach provides a powerful new technique to study HNL production at future fixed-target experiments and can readily be extended to other light BSM particle production within a broader class of dark sector models.

Speaker: Francis Burk

15:30 The Cosmic Neutrino Background is within Reach of Future Neutrino Telescopes

As an extension of our previous work on the Diffuse Boosted Cosmic Neutrino Background, we further incorporate charged current processes and deep inelastic scattering. We found that deep inelastic scattering significantly enhances the boosted flux at high energies, and that IceCube already places an upper limit on the $C\nu B$ overdensity of $\sim O(10^2) - O(10^3)$. Furthermore, the combination of 10 future neutrino telescopes with similar sensitivity to IceCube-Gen2 will allow us to test the $\Lambda$CDM expected $C\nu B$ density for a lightest neutrino mass $\sim 0.1\mathrm{eV} - 0.2 \mathrm{eV}$.

Speaker: Xiaolin Qi (Virginia Tech)

15:45 Reshaping the neutrino fog

The neutrino fog represents a fundamental irreducible sensitivity limit for dark matter direct detection arising from coherent elastic neutrino-nucleus scattering (CEvNS). We present a precision calculation of the neutrino fog for spin-independent (SI), spin-dependent proton-coupled (SDp), and spin-dependent neutron-coupled (SDn) WIMP interactions on a natural xenon target, derived by matching a relativistic effective field theory of WIMP interactions with quarks onto nucleon-level effective couplings at the hadronic scale, which are subsequently expressed in terms of a complete basis of Galilean-invariant non-relativistic effective operators governing the WIMP-nucleus interaction at the nuclear scale. Nuclear shell-model response functions replace the Helm form factor approximation for both the WIMP signal and the CEvNS neutrino background, yielding spectral differences that induce a systematic rescaling of the fog boundary for WIMP masses above 50 GeV across all three interaction channels. Steep vertical drops in the fog are observed in the 10–100 GeV mass range, whose origin is investigated in terms of kinematic degeneracy between the atmospheric neutrino background and the WIMP recoil spectrum.

Speaker: Julian Rovner (University of Cincinnati)

14:00 → 16:00 New Developments in Theory: Session 2

14:00 Pure Gauge Theories in Two Dimensions

We provide a detailed review and extension of compact, exactly solvable, pure Abelian and non-Abelian gauge theories in 1+1 dimensions, which have many similarities to (3+1)D pure Yang-Mills like confinement and a theta term. We focus on the U(1), SU(N) and SU(N)/ZN gauge groups​. For the Abelian (1+1)D QED theory, we present a non-relativistic quantum mechanics calculation of the electric dipole moment (EDM) for neutral bound states of heavy quarks​, which is shown to diverge as the vacuum angle θ approaches π, marking a deconfinement transition. This characterizes a "Strong C/P Problem" in (1+1)D, where the EDM is T-even but C- and P-odd. We provide exact analytic expressions for the partition function and Wilson loops (showing area law) with full θ dependence, which could serve as a useful check for lattice and quantum simulations with the sign problem. Using the modular inversion property of Jacobi theta functions (Poisson summation), we map the sum over energy eigenvalues in the canonical formulation of the partition function to a sum over topological instanton sectors. The partition function is seen going to zero in the strong coupling limit when θ = π, as expected.

In the non-Abelian sector, explicit analytic partition functions on a torus for SU(N=2,3) are already known and the Hilbert space of SU(N)/ZN​ theories decomposes into N sectors characterized by different weightings of the second Stiefel-Whitney class. As ongoing work, we are attempting to reinterpret these partition functions from the perspective of 1/N "fractional instantons" that cannot be lifted to the universal enveloping group SU(N), and we do so by studying all incontractible loops in the moduli space of flat connections (i.e. the maximal torus quotiented by the Weyl group).

Speaker: Digvijay Roy Varier (University of California, Berkeley)

14:15 Dynamics for theories with higher-order interference (a proposal)

It is well-known that the quantum interference pattern in a two-slit experiment cannot be reduced to a sum of two single-slit patterns. However, as first noted by Rafael Sorkin, even when one has a variant of such an experiment consisting of three or more slits, quantum mechanics predicts that the resulting interference pattern can be reduced to a sum of two-slit patterns. Therefore, quantum mechanics is a theory exhibiting second-order interference but not higher.

Given that, in principle, Nature could admit interference of higher-order, such a possibility has been extensively investigated both experimentally and theoretically. Higher-order interference has been constrained via a wide range of interferometric experiments, often designed as tests of the Born rule. On the theoretical side, there exist frameworks that allow for the possibility of higher-order interference. However, the analytic form of an equation of motion (akin to Heisenberg’s equation of motion for quantum mechanics) for such theories has remained an open problem. In this talk, we will discuss our proposal for a possible dynamics describing theories exhibiting third-order interference.

Speaker: Nabin Bhatta (Virginia Tech)

14:30 Light KK Gravitons from Extended Warped Extra Dimensions at DUNE

We study extended warped extra-dimensional models in which gravity propagates to a deep infrared brane with warped scale $\Lambda_{IR} \sim \mathcal{O}(\mathrm{MeV})$, leading to a dense KK graviton tower with MeV-scale spacing. We present a DUNE-motivated model realization of the photon portal to this tower. The visible electroweak gauge sector extends to an intermediate GeV brane, and brane-localized kinetic terms are used to control precision-electroweak constraints while preserving an enhanced coupling between KK gravitons and the photon. Primakoff-like production at DUNE then can produce GeV-scale KK gravitons, which then cascade down the tower to the lightest mode. If the radion channel is kinematically closed for the terminal state, the lightest KK graviton becomes long lived and decays visibly to diphotons. In this talk I discuss the resulting rich phenomenology of production, cascade decays, and signals at DUNE, and outline the main theoretical and precision constraints relevant for this extended warped scenario.

Speaker: Ankur Verma (University of South Dakota)

14:45 Asymptotic Velocity Domination in quantized polarized Gowdy Cosmologies

Asymptotic velocity domination (AVD) posits that when back-propagated to the Big Bang generic cosmological spacetimes solve a drastically simplified version of the Einstein field equations, where all dynamical spatial gradients are absent (similar as in the Belinski-Khalatnikov-Lifshitz scenario). Conversely, a solution can in principle be reconstructed from its behavior near the Big Bang. This property has been rigorously proven for the Gowdy class of cosmologies, both polarized and unpolarized. Here we establish for the polarized case a quantum version of the AVD property formulated in terms of two-point functions of (the integrands of) Dirac observables: these correlators approach their much simpler velocity dominated counterparts when the time support is back-propagated to the Big Bang. Conversely, the full correlators can be expressed as a uniformly convergent series in averaged spatial gradients of the velocity dominated ones.

Speaker: Mahdi Sedighi Jafari (University of Pittsburgh)

15:00 Entanglement, Yang-Mills, and the Scattering Matrix as an SU(N)-equivariant Kernel

Recent work has highlighted a surprising connection between quantum information and high energy physics.In this talk, I will discuss how symmetry and general consistency conditions constrain the entanglement structure of scattering amplitudes, largely independent of detailed dynamics.In Yang–Mills theory, symmetry alone strongly constrains this structure, leading to universal entanglement features independent of detailed dynamics. I will also show how these features can be used to probe effective field theory deformations, and how simple entanglement-based constraints can uniquely select Yang–Mills theory within a broad class of interactions. These results suggest a new, information-theoretic perspective on the structure of quantum field theories.

Speaker: Rahul Muraleedharan (University of Oklahoma)

15:15 Strongly Coupled Quantum Forces

Quantum forces are long-range interactions arising from vacuum fluctuations of mediator fields. Conventionally, they are computed via one-loop Feynman diagrams. In this talk, I present a novel framework that instead directly evaluates the mediator field's quantum fluctuations by solving its quantized equation of motion with appropriate boundary conditions. This approach extends beyond the Born approximation into strong-coupling regimes. I will show that our results reproduce known expressions at weak coupling, while at strong coupling the force acquires a modifying factor that can suppress or enhance the effect. I will also discuss how quantum forces intrinsically violate the superposition principle, making this framework a potentially useful tool for probing non-perturbative effects in the infrared regime.

Speaker: Chinhsan Sieng (Cornell University)

15:30 Massive 1→3 Splitting Functions Beyond Kinematical Limits

Splitting functions are the factorized forms of collinear dynamics in perturbative QCD and are central ingredients in parton shower models, whose precision is crucial for finding and understanding new physics in collider events. We present a compact form of the massive 1→3 tree-level QCD splitting functions, obtained without reference to soft or quasi-collinear limits. The triple-collinear kernels are computed by layering scalar (semi-classical) interaction and fermionic interference terms, yielding a decomposition in terms of lower-order expressions, scalar dipole antenna functions, and pure higher-order remainders. The two-gluon radiator functions arising in this context are novel and generalize expressions previously obtained from the double-soft approximation. We compare against existing massive and massless results, and discuss how this decomposition enables systematic integration of the 1→3 splittings into current Monte-Carlo simulations, extending the precision of parton shower calculations.

Speaker: Grant Whitman (Brown University)

15:45 Using symmetry breaking to obtain multiple copies of SU(M) related by a discrete, cyclic gauge symmetry

Without fine-tuning, it is difficult to maintain the utility of the axion as candidate solution to the strong CP problem when it is embedded in UV models due to additional interactions that spoil the IR phenomenology. Anson Hook has presented a model where the axion potential is naturally exponentially suppressed through its interactions with N copies of the same fermionic sector. Although each individual copy contributes a potentially quality-spoiling effective potential, the summation over all N sectors produces cancellations among them which eliminates the lowest-order dependence on the axion and flattens its total potential. The model hinges on a discrete ZN symmetry shifting one copy of the fermions to another cyclically. Here we examine how to embed this system in a UV completion. With a suitable choice of representation, we break SU(NM) into N tensored copies of SU(M) twisted by a semi-direct product with ZN which acts by the desired cyclic permutation.

Speaker: Noah McNeal (Harvard University)

14:00 → 16:00 New Physics at Future Colliders: EFT, DM

14:00 Estimation of NLO-in-EFT Errors for Collider SMEFT Searches

I present a novel technique for estimation of uncertainties arising from truncation of the EFT expansion perturbation series which exploits the calculability of partial next-order effects while removing degeneracies in effects of different operator combinations to provide a minimal (observable-dependent) set of nuisance parameters. This gives a manageable number of nuisances to be included in producing a conservative constraint on SMEFT parameters, which has been cross-checked against full next-order calculations in example processes and shown to contain the relevant effects. The procedure is process-independent and straightforward to apply.

Speaker: William Shepherd

14:15 Probing Top Quark - Electron Interactions at Future Colliders

Top quark interactions offer a window into possible new high scale physics and many models of new physics predict that the top quark interactions will deviate significantly from those predicted by the Standard Model (SM). We present an analysis of the experimental restrictions on anomalous 4-fermion $e^+e^- t {\overline{t}}$ operators that is accurate to next-to-leading order (NLO) in both the electroweak and QCD interactions within the Standard Model Effective Field Theory framework. At NLO, there is sensitivity to an extended set of anomalous interactions beyond those probed at leading order. A comparison of current limits from electroweak precision observables, along with expected future limits from Drell-Yan and $t{\overline{t}}e^+e^-$ production at the high luminosity LHC, from deep inelastic scattering at the EIC, and from projected sensitivities at the future FCC-ee and CEPC machines demonstrates that each of these programs extends the precision understanding of the interactions of top quarks.

Speaker: Hongkai Liu (BNL)

14:30 Probing light axion-like particles via photon conversions in the CMS tracker

Axion-like particles (ALPs) with masses between 10 MeV and 10 GeV are notoriously hard to probe. The LHC experiments are uniquely positioned to test ALPs with such masses. The dominant production mechanism of electromagnetically coupled ALPs at the LHC is vector boson fusion (VBF). For light ALPs, the photons resulting from their decay tend to overlap, appearing as a single object in the the electromagnetic calorimeter. We propose a search strategy which exploits the superior spatial resolution of the all-silicon tracker (∼10–50 μm) of the Compact Muon Solenoid experiment to target the electrons from converted photons and reconstruct the displaced decay vertex of ALPs. We present the first projected sensitivity of CMS to this signature, using alternative trigger strategies which place relaxed requirements on the features of VBF jets to enhance signal efficiency. By turning a long-standing reconstruction challenge into an experimental handle, this strategy opens a new window onto an ALP parameter space previously unexplored.

Speaker: Sena Durgut (Carnegie-Mellon University (US))

14:45 Probing Dimension-6 SMEFT Operators in Rare Z and Higgs Decays at the LHC and Beyond

Motivated by the upcoming High-Luminosity Large Hadron Collider upgrade and the ongoing efforts towards a Muon Collider, we investigate the potential of future colliders to probe beyond the Standard Model physics through rare decay observables, all within the model-independent dimension-6 Standard Model Effective Field Theory (SMEFT) framework. We focus on operators involving electroweak gauge fields or fermionic currents coupled to the electroweak sector to understand their role in rare Z and Higgs decay topologies. We discuss how invariant mass distributions in multi-lepton outgoing particles from these decay topologies can provide a way to enhance the sensitivity of future colliders to these rare decay processes and thus improve constraints relative to existing bounds.

Speaker: Inci Karaaslan (University of Chicago (US))

15:00 The Geometry of SMEFT: From Field-Space Geometry to Collider Signatures

Effective Field Theories (EFTs) are a framework to probe physics beyond the Standard Model (BSM) in a model independent way. The Standard Model Effective Theory (SMEFT) provides an expansion of higher-dimensional operators that encode the effects of heavy new physics; however, in the operator basis there exists a redundancy in the space of field redefinitions which leaves on-shell amplitudes invariant. A geometric formulation of the SMEFT reframes the language of an arbitrary operator-basis approach to clearly represent fields as coordinates and field redefinitions as coordinate transformations. This geometric viewpoint motivates the adoption of Riemann Normal Coordinates (RNC) to remove spurious kinematic pole structures. Implementing the global symmetry in the RNC basis enables an all-order expansion of the field space metric and associated operators, providing a covariant description of N-point off-shell scattering amplitudes in the high energy limit around the vacuum expectation value (vev). Such a geometric perspective can aid in the systematic analysis of collider data for future BSM searches by highlighting observable signatures of new physics.

Speaker: Cristofer Caballeros (University of Florida)

15:15 Searches for dark sector signatures with CMS

Among the intriguing scenarios of new physics that provide explanation to several shortcomings of the Standard Model (SM), hidden valley scenarios include a Dark Sector that extends the SM with a non-Abelian gauge group, similar to quantum chromodynamics with new matter and gauge fields analogous to the SM quark and gluon fields. This may result in a rich phenomenology which we can access through portal interactions. In this talk we present the most recent results from CMS that explore such Dark Sectors by exploiting dedicated data streams and innovative usage of the CMS detector.

Speaker: Gianfranco De Castro (Cornell University (US))

15:30 Probing Higgs-Gauge Interactions at HL-LHC and Future Lepton Colliders

We investigate Higgs-gauge boson interactions using effective field theory approaches at both hadron and lepton collider frontiers. At the HL-LHC, we analyze the $Zh$ associated production mode by incorporating Higgs-gauge coupling modifiers in the $\kappa$ framework and dimension 6 SMEFT operators involving Higgs-current and dipole structures. Machine learning techniques are employed to enhance sensitivity to these interactions, highlighting their growing relevance in probing high-energy effects. Complementarily, we study $hVV$ $(V=Z,\gamma,W)$ couplings at future $e^{+}e^{-}$ colliders with $\sqrt{s} = 250$ GeV, using optimal observable and spin-asymmetry techniques to constrain both CP-even and CP-odd operators through using Higgs decay modes: $b\overline{b}$, $WW^{*}$, and $ZZ^{*}$. Together, these studies illustrate how precision measurements at lepton colliders, in synergy with LHC analyses, can substantially sharpen constraints on anomalous Higgs-gauge interactions and reveal potential imprints of new physics.

Speaker: Abhik Sarkar (Indian Institute of Technology Guwahati)

15:45 -

16:00 → 16:30 Coffee Break

16:30 → 18:30 Astro-particle: Dark Matter

16:30 Heavy dark matter in rapidly evolving massive stars

his talk will address the impact of heavy dark matter (DM) captured in massive stars via scattering(s) with the star constituents. We focus on the first stars and use stellar evolution simulations to track down how DM capture evolves over time from the zero-age main sequence to the late metal-rich stages of stellar evolution. During the early hydrogen-helium-dominated phase, the capture process is well described by scattering with two targets. As a star evolves, metal production leads to the formation of a dense core surrounded by a lighter envelope, which significantly enhances the capture of ultra-heavy DM. We find that heavy DM would be able to thermalize and achieve capture-annihilation equilibrium within a massive star's lifetime for regions of the parameter space not excluded by direct detection. Our results highlight the dependence of DM capture on the stellar evolutionary stage, composition, and halo location, demonstrating that accurate modeling of massive stars is essential for constraining heavy DM with primordial stellar populations.

Speaker: Walter Tangarife (Loyola University Chicago)

16:45 Enabling Forbidden Dark Matter from a First-Order Phase Transition

We propose a simple yet testable framework for light fermion dark matter (DM) with mass in the MeV--GeV range, charged under a dark $U(1)_D$ gauge symmetry. The $U(1)_D$ is spontaneously broken by a scalar field $\Phi$, giving mass to the dark gauge boson $X_D$. The dominant DM annihilation proceeds via a forbidden channel, where the DM pair annihilates into slightly heavier dark gauge bosons and scalars after the dark-sector phase transition. Once the dark-sector phase transition occurs, the induced mass gap activates the forbidden annihilation channel, which in turn determines the DM relic abundance and naturally suppresses late-time annihilation. As a result, the scenario avoids stringent cosmic microwave background and indirect detection constraints that typically exclude thermal light DM. Moreover, the same symmetry-breaking phase transition is strongly first-order, producing a stochastic gravitational wave background that could be probed by upcoming space-based interferometers and pulsar timing arrays. We demonstrate that achieving the observed DM abundance tightly correlates the DM mass with the nucleation temperature of the phase transition. Thus, this setup links the DM relic abundance, dark-sector dynamics, and gravitational wave signals, offering complementary paths for discovery in both terrestrial and cosmological observations.

Speaker: Mr Partha Kumar Paul (Indian Institute of Technology Hyderabad)

17:00 Gaia at the Forefront of Dissipative Dark Matter Searches: Exchanges

One of the major scientific milestones of the Gaia mission has been the achievement of an improved stellar binary population census and the discovery of rare objects such as black hole (BH)-star binaries. High precision astrometric measurements of binary separations and mass ratios have an application in dark sector physics, as stellar binaries are highly sensitive to the spatial as well as the velocity distribution of perturbers. This makes them a sensitive probe of dissipative dark sectors, where a subcomponent of dark matter can cool to form a dark disk as well as dark compact objects (including black holes). In this work, we consider the observational implications of the existence of a dark disk on the formation rate of BH-star binaries by considering exchanges between dark perturbers and stellar (star-star) binaries. Unless the scale height of the dark disk equilibrates with the stellar thin disk, we find the rate of these exchange interactions is in excess of the rate expected from observations, arising largely due to the much smaller velocity dispersion of the dark compact objects within a dark disk which is co-rotating with the Standard Model galactic disk. Comparing with observation, we set potentially competitive constraints on the DDM parameter space, making the Gaia mission an important testbed for dissipative dark sector physics.

Speaker: Jackie Lodman (Harvard University)

17:15 Ultra-Strongly Self-Interacting Dark Matter and the Origin of Little Red Dots

With the advent of the James Webb Space Telescope (JWST), observational probes of the structure of objects in the early universe are more readily available. In particular, the discovery of high-redshift (z ~ 10) Supermassive Black Holes (SMBHs) challenges the typical formation channels of these objects which cannot form sufficiently massive seeds or grow them within these timescales without significant periods of Super-Eddington accretion. Similarly, in the past few years, a brand new class of high-redshift objects has been discovered, called “Little Red Dots” (LRDs) - thought to be heavily dust enshrouded SMBHs ($10^{6}$ - $10^{8}$ $M_{\odot}$) hosted in a highly compact galaxy approximately 50 parsecs in size.

To address the potential formation of these objects, we have introduced a model of self-interacting dark matter (SIDM), where a small fraction of the SIDM is ultra-strongly self-interacting (uSIDM). The typical cross-sections of SIDM are on the order of 0.1-10 $\text{cm}^{2}/\text{g}$, whereas uSIDM cross-sections are on the order of $10^{3}$-$10^{4}$ $\text{cm}^{2}/\text{g}$. With such high cross-sections, the uSIDM undergoes rapid gravothermal evolution leading to a full core-collapse of the innermost portion of the dark matter halo. The rapid timescale for this collapse allows for the formation of a heavy SMBH seed well within the observed formation times; thus uSIDM is a prime candidate for the creation of LRDs. Subsequent sub-Eddington accretion grows the seeds to match the observed SMBH masses, LRD mass function, and predicts a testable clustering bias for LRDs at z ~ 5.

Speaker: M. Grant Roberts (University of California, Santa Cruz)

17:30 Probing Ultralight Dark Matter via Caustic Crossings in Giant Arcs

Ultralight Dark Matter (ULDM) is a compelling alternative to the WIMP paradigm, offering potential solutions to small-scale structure challenges through its wave-like behavior. A hallmark of ULDM is the presence of interference-induced overdensities, or "Extended Dark Objects" (EDOs), which arise naturally within the dark matter halo. In this talk, we present a method to constrain the ULDM mass and fraction using the observation of highly magnified stars near the caustics of giant arcs in galaxy clusters.

Utilizing the BBKS formalism to characterize the statistical properties of these overdensities, we calculate the expected optical depth for microlensing events. We demonstrate that sufficiently dense EDOs can significantly alter the magnification of background stars, such as the Icarus event (MACS J1149 Lensed Star 1), potentially leading to peak magnitudes that exceed observational thresholds. By comparing theoretical predictions with this extreme magnification event, we derive constraints on the ULDM parameter space, specifically the particle mass and the dark matter fraction. Our results highlight the power of caustic crossings in galaxy clusters as a high-resolution laboratory for testing the particle nature of dark matter.

Speaker: Carlos Ramos Portalatino (University of Florida)

17:45 Dark Secrets of Baryons: Illuminating Dark Matter-Baryon Interactions with JWST

The James Webb Space Telescope (JWST) has discovered numerous bright galaxies at high redshifts ($z\approx 10-14$). Many astrophysical models and beyond the Standard Model physics scenarios have been proposed to explain these observations. We investigate, for the first time, the implications of dark matter (DM) scattering with baryons (protons and electrons) in light of the JWST UV luminosity function (UVLF) observations. These interactions suppress structure formation on galactic scales, which may have an observable effect on the UVLF measurements at high redshifts. Using a recent galaxy formation model designed to explain high redshift observations, we obtain strong upper limits on DM-baryon scattering cross-sections and explore new regions of the parameter space. For DM-proton scattering with cross-section $\propto v^{-2}$ velocity dependence, we obtain the strongest limit for DM masses of $\sim 1 - 500$ MeV. For other cases that we study (DM-proton scattering cross-section $\propto v^{0},\,v^{-4}$ and DM-electron scattering cross-section $\propto v^{0},\,v^{-2},\,v^{-4}$, our limits are competitive with those obtained from other cosmological observables. Our study highlights the potential of JWST observations as a novel and powerful probe of non-gravitational interactions of DM.

Speaker: Souradeep Das (Ohio State University)

18:00 Circumstellar Medium of Supernovae as New Probes for Feebly-interacting Particles

We propose a novel strategy to probe feebly-interacting particles (FIPs) by exploiting the dense, confined circumstellar medium (CSM) surrounding core-collapse supernovae (CCSNe). FIPs produced in the proto-neutron star can deposit substantial visible energy into the CSM via decay prior to the shock breakout from the progenitor star. This energy injection heats and ionizes the CSM, establishing a FIP-induced photosphere that generates distinctive precursor blackbody emission. Using early-time observations of SN 2023ixf, we translate the non-detection of excessive precursor luminosity into stringent new constraints on MeV-scale dark photons as an exemplary model. Our results significantly extend existing CCSN bounds and exclude previously unexplored regions of parameter space. We further demonstrate that the FIP-induced dust sublimation offers robust diagnostics for future Galactic SNe, opening a new avenue to explore the dark sector.

Speaker: Yu Cheng

18:15 Revisiting extremely high energy QED bremsstrahlung in matter: large modifications to the LPM effect

Very high energy electrons initiate electromagnetic showers in ordinary matter that branch and multiply through bremsstrahlung and pair production. At extremely high energies, the quantum mechanical duration of these processes becomes longer than the mean free time to elastically scatter from the medium, which leads to a very significant suppression of bremsstrahlung (and pair production) known as the Landau-Pomeranchuk-Migdal (LPM) effect. We revisit the LPM effect for bremsstrahlung of energy kγ from an electron of energy E. We find that there are very large corrections to the LPM bremsstrahlung rate for certain regions of $(k_\gamma, E)$ due to quantum overlap of bremsstrahlung and subsequent pair production. This possibility was first raised in the 1960s, when it was argued qualitatively that pair production would significantly decrease the bremsstrahlung rate in those regions of $(k_\gamma, E)$ compared to the already-suppressed LPM bremsstrahlung rate. We find the opposite -- quantum overlap of bremsstrahlung with pair production significantly increases the bremsstrahlung rate compared to the LPM calculation -- and we verify our qualitative arguments with an analytic calculation of the effect.

Speaker: Joshua Bautista (University of Virginia)

16:30 → 18:30 Cosmology: Axions

16:30 Axions on a Hyperbolic Ride

CMB limits on isocurvature are often taken to exclude high-scale inflation with large QCD axion decay constants in pre-inflationary PQ models. We show this can be avoided via PQ field-space geometry.

With a nonlinear sigma-model kinetic term, the effective decay constant is enhanced during inflation, suppressing isocurvature without extra couplings or PQ breaking. For a hyperbolic field-space geometry, the suppression of isocurvature is exponentially sensitive, and the same geometry also yields a time-dependent axion mass that controls the tilt and running, yielding a blue-tilted spectrum.

This allows $H_{\rm inf}\sim 10^{13}$ GeV with $f_{\rm a}\sim 10^{14-16}$ GeV, reopening previously excluded parameter space. We present ‘observable’ benchmarks and a semi-analytic template that relates the scale-dependence of isocurvature to the geometric lever arm, crucially providing a direct phenomenological probe on PQ field-space geometry.

Speaker: Dr Sai Chaitanya Tadepalli (Dept of Physics, Indiana University, Bloomington)

16:45 Probing Dark Matter Decays to Axions via Axion-Photon Conversion in Filaments

Axions produced from dark matter decays can convert to photons in the magnetic fields of cosmological filaments, resulting in an isotropic gamma ray background flux. We present new indirect detection constraints on the axion mass and axion-photon coupling, for GeV- to TeV-scale dark matter with a decay lifetime below $10^{30}$ sec, by constraining this flux. We exclude significant parameter space for axion masses below $10^{-5}$ eV, including a portion of the QCD axion band, for $1$ TeV dark matter with a decay lifetime of $10^{19}$ sec, and $250$ nG filaments.

Speaker: Matthew Baldwin

17:00 QCD Axion Domain Walls from Super-Cooling First Order Phase Transition

The QCD axion is a well-motivated hypothetical particle beyond the Standard Model (SM) and a compelling dark matter candidate. Its relic abundance is highly sensitive to the thermal history of the universe when the temperature is around the QCD confinement scale. Meanwhile, the NANOGrav Collaboration has reported evidence for a stochastic gravitational wave background, which could originate from a supercooled first-order phase transition (FOPT) with a nucleation temperature around the O(MeV-GeV) scale. We explore how such an FOPT might alter the evolution of the QCD axion. Our findings suggest that it could induce the axion to go through a short stage of mini kinetic misalignment. Moreover, in some parameter regime, the formation of QCD axion domain walls becomes generically expected. This has intriguing implications for both the existence of the QCD axion and the FOPT interpretation of the NANOGrav signal.

Speaker: Kunfeng Lyu

17:15 Dynamical Heating from Dark Compact Objects and Axion Minihalos

The temperature of baryons at the end of the cosmic dark ages can be inferred from observations of the 21-cm hyperfine transition in neutral hydrogen. Any energy injection from the dark sector can therefore be detected through these measurements. Dark compact objects and dark-matter substructures can modify the baryon temperature by transferring heat via dynamical friction. In this work, we evaluate the prospects for detecting dynamical friction-induced heating from dark compact objects with a mass in the range 10^2 to 10^5 solar masses, as well as from axion minihalos, using upcoming 21-cm experiments. We find that both the 21-cm global signal and power-spectrum measurements will be sensitive to dark compact objects that constitute about 10% of the dark matter, and will substantially improve our sensitivity to axion-like particles with masses in the range 10^-18 eV to 10^-9 eV.

Speaker: Badal Bhalla (University of Oklahoma)

17:30 Putting the Brakes on Axion Strings: Friction and Its Impact on the QCD Axion Abundance

A compelling production mechanism for QCD axion dark matter is from the scaling dynamics of early universe axion strings. We show that in DFSZ-like models containing tree-level interactions between fermions and the axion, friction between the thermal bath and the axion string drastically changes the behavior of the axion string network for lower $f_a$ values. Friction delays the onset of scaling and increases the energy density of axions. Once the effects of friction are included, we argue that in addition to the standard value of $m_a \sim$ meV, $m_a \sim 0.1$ eV also reproduces the dark matter energy density.

Speaker: Rajrupa Mondal (University of Maryland College Park)

17:45 Constraints on Axion Dark Matter Isocurvature from CMB

Measurements of the Cosmic Microwave Background (CMB) have confirmed a nearly scale-invariant primordial spectrum of adiabatic perturbations, in which the density fluctuations of radiation, baryons, and dark matter are in phase. However, primordial perturbations may also include an isocurvature component, in which the relative density fluctuations of individual species such as dark matter (DM) deviate from the adiabatic mode. Such isocurvature modes provide a powerful probe of physics beyond standard model of particle physics, for instance, pre-inflationary QCD axion DM. In this talk, I will present the most up-to-date constraints on pre-inflationary axion DM isocurvature using CMB measurements from Planck, as well as from the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT), for both flat and tilted primordial spectra. I will then discuss the theoretical implications of these isocurvature constraints

Speaker: Praniti Singh (Brown University (US))

18:00 Cosmological Aspects of Axion-Monopole Interactions

We propose a minimal and natural dark-sector framework in which dark matter is composed of magnetic monopoles coupled to a light axion field. Through the Witten effect, the axion background induces electric charge on the monopoles, turning them into dyons that in turn modify the axion potential. This monopole-dependent axion mass provides a simple, radiatively stable mechanism for dark-sector interactions and allows the axion to act as a dynamical dark-energy component. The resulting slow evolution of the axion field at late times can naturally produce the polarization rotation associated with the reported CMB cosmic birefringence signal and may also accommodate the evolving dark-energy behavior suggested by recent DESI data. This framework offers a unified and economical explanation for multiple late-time cosmological hints.

Speaker: Hengameh Bagherian (University of Chicago)

18:15 Tackling the Axion Isocurvature Problem with Bulk Modulus Kination

Extra-dimensional scenarios for the QCD axion are well motivated to address the quality problem. However, like other pre-inflationary axion theories, they suffer from the axion isocurvature problem where QCD axion dark matter is incompatible with high scale inflation due to CMB isocurvature bounds. We tackle this problem by utilizing an additional ingredient generically predicted by extra dimensional theories: a scalar modulus field in the 4D EFT that controls the size of the extra dimensions and the axion’s decay constant. During an epoch of modulus kination between inflation and reheating, the axion decay constant dynamically decreases, permitting a higher inflationary energy scale while remaining consistent with isocurvature bounds. However, modulus kination tends to suffer from the overshoot problem, leading to decompactification of the extra dimensions. In this work, we investigate how to trap the modulus field with generic extra-dimensional field contents and determine the associated change in the QCD axion decay constant. Towards this end, we calculate scalar and gauge field particle production during the inflation—kination transition and comment on analogies to the tunneling problem in quantum mechanics.

Speaker: Chandrika Chandrashekar (Harvard University)

16:30 → 18:30 Dark Matter: Astrophysics

16:30 Machine Learning Does It and Does It Better: Unearthing Primordial Dark-Matter Velocities from the Matter Power Spectrum

One effective way of learning about the production and properties of dark matter in the early universe is by extracting information about the primordial dark-matter phase-space distribution from the matter power spectrum. Recently a simple empirical formula was introduced which is capable of reproducing most of the salient features of the dark-matter phase-space distribution — even in situations in which this distribution is non-thermal, multi-modal, or exhibits other complicated features. In this talk, I examine the extent to which machine-learning techniques can improve upon this analytic approach and demonstrate that these techniques not only succeed in reconstructing the dark-matter phase-space distribution with greater accuracy, but are also applicable to a broader range of matter power spectra.

Speaker: Brooks Thomas

16:45 X-ray femtolensing probes asteroid-mass black holes

The asteroid-mass regime is the key remaining window in which primordial black holes could constitute all of dark matter. I will present a new method to probe a substantial portion of this window using X-ray femtolensing. While photometric microlensing requires long observations of very stable compact sources, the energy-dependent features imprinted onto X-ray spectra furnish a clean target with relatively little in the way of astrophysical backgrounds. I will demonstrate that that per-event fringe detection is straightforward for asteroid-mass objects lensing bright compact Galactic sources, meaning that the only bottleneck is the lensing event rate. Remarkably, the ~35 megaseconds of archival data already in hand from RXTE and NICER are sufficient to probe PBH dark matter at masses of order $10^{19}\,{\rm g}$ with existing data. I will further explain how upcoming data will make these bounds substantially more robust even without any dedicated searches.

Speaker: Benjamin Lehmann (Massachusetts Institute of Technology)

17:00 Structure Formation with Dark Magnetohydrodynamics

Long-range interactions in the dark sector can give rise to collective plasma phenomena that are capable of modifying the evolution of dark matter halos. We present the first study of gravitational collapse in a secluded dark $U(1)_D$ model using a magnetohydrodynamic description of the dark matter. We show that dark magnetic fields generate an anisotropic pressure that alters the Jeans scale and suppresses small-scale power in a direction-dependent manner. For a range of primordial magnetic spectral indices, this effect produces distinctive modifications to the linear matter power spectrum. We find that current observations cannot yet constrain viable dark magnetic fields, as CMB tensor modes mostly provide more stringent constraints. Nevertheless, forthcoming high-resolution probes of the matter power spectrum (CMB-HD lensing, HERA, and EDGES) will be able to test these predictions and are sensitive to dark charge-to-mass ratios in the range $10^{−20}\text{ GeV}^{−1}≲q_\chi/m_\chi≲10^{−14}\text{ GeV}^{−1}$.

Speaker: Pierce Giffin

17:15 Set the Night on FIRE: Building an Empirical Local Dark Matter Velocity Distribution

The majority of terrestrial direct detection experiments for Dark Matter (DM) rely on the Standard Halo Model (SHM), which assumes the local DM velocity distribution follows a Maxwell–Boltzmann distribution. However, galaxy mergers can deposit DM that remains kinematically clustered today, inducing deviations from the smooth SHM prediction. Previous studies have suggested that the local stellar velocity distribution may serve as a tracer for DM populations originating from the same progenitor systems. In this work, we systematically investigate how merger mass and accretion time affect the correlation between local stellar and DM velocity distributions in Milky Way–like galaxies from the FIRE-2 simulations. We find a strong correlation between traceable DM components and their stellar counterparts, with the tightest correspondence arising from lower-mass mergers accreted at earlier cosmic times. For the remaining DM that lacks an identifiable stellar counterpart, which dominate the full DM fraction, we find that its velocity distribution is well described by a component-wise generalized Gaussian. Combining these two ingredients, we reconstruct the full local DM velocity distribution. This framework captures merger-induced features—such as co-rotation of accreted material with the galactic disk—that are entirely absent in the SHM. Finally, we propagate uncertainties through the reconstruction and show that they are dominated by the stellar mass–halo mass relation, which is unlikely to improve substantially in the near term. We therefore argue that this framework approaches the current limit of our ability to characterize the local DM velocity distribution.

Speaker: Xiuyuan Zhang

17:30 Jupiter is a Dark Matter Refrigerator: Electron Degeneracy Inhibits Evaporation

Jupiter is an excellent target for dark matter searches. However, the minimum testable dark matter mass is set by evaporation, where thermal interactions with Jovian material exceed the gravitational potential and remove dark matter from the planet, limiting search sensitivity. We show that in the case of leptophilic dark matter, evaporation is strongly suppressed because most electrons are confined into metallic and solid layers where %they completely fill the Fermi-Dirac distribution and
Pauli blocking forbids them from upscattering dark matter. We show that leptophilic dark matter remains trapped in Jupiter on Gyr timescales down to masses as low as $\sim$10 MeV, opening new sensitivities for sub-GeV dark matter searches.

Speaker: Tran Quang Thong Nguyen (Stockholm University)

17:45 Screened Forces in a QCD-Like Dark Sector on Galactic Scales

Persistent small-scale challenges to the ΛCDM cosmological model have motivated the consideration of dark matter models with richer phenomenology. We consider a dark QCD scenario in which dark axions mediate a screened force between dark baryons within dark matter halos. Finite-density corrections to the dark QCD quark condensate introduce a density-dependent interaction term between dark axions and dark baryons, with a $\mathbb{Z}_2$ symmetry breaking, analogous to the symmetron mechanism. We use the FIRE-2 cosmological simulations, spanning dwarf to group halo mass scales, to test the feasibility of realistic dark matter halo profiles sourcing the dark axion. Through multi-objective optimization, we identify 3 example parameter sets that produce attractive forces of order $\sim 1-5$ times the strength of gravity, active over distances ranging from $\sim 50$ kpc to $\sim 1$ Mpc from the center of the halo, or $\sim 0.2 R_{\rm Vir}$ to $\sim 5 R_{\rm Vir}$ for a Milky Way-like halo. The force profiles generally follow the same structure: a screened center, a transition region where the force is active, and an outer decay to zero. Though our results only reflect the instant in which the axion is sourced, we tested this model against dynamical stability criteria including the free-fall time scale and Jeans length. These predict a spherical shell around the halo, aligning with the peak of the force profile, where circular orbits may be unstable and the halo is more vulnerable to collapse. The free-fall time is also lowered, suggesting that this DM model will result in large-scale rearrangement of the dark matter density.

Speaker: Mathilda Denison (University of Pennsylvania)

18:00 First-Order QED Corrections to the Electron Spectrum of Hawking Radiation from Asteroid-Mass Primordial Black Holes: Formalism and Numerical Evaluation of Dissipative Interactions

Primordial black holes (PBHs) in the asteroid-mass window ($10^{17}-10^{22}$ g) are a well-motivated dark-matter candidate, and Hawking radiation sets constraints based on their evaporation outcomes such as photons, electrons and positrons. In this specific mass range, the Hawking temperatures are high enough to facilitate the generation of electron-positron pairs, which can contribute to the 511 keV annihilation line and impose further constraints on the abundance of PBHs. Accurate predictions therefore require a systematic QED calculation of the electron spectrum from Hawking radiation. In this study, the first-order QED correction to the dissipative part of the electron spectrum in a Schwarzschild black-hole background is derived using the interaction-Hamiltonian formalism. The resulting correction is organized into distinct channels, and the infrared behavior of the correction in the soft-photon limit is analyzed in detail. Preliminary numerical results and progress toward a full numerical evaluation will also be presented.

Speaker: Bowen Chen (Ohio State University)

18:15 Searching for Ultralight Scalar Dark Matter with Clocks in Low Earth Orbit

Ultralight dark matter with quadratic couplings to the Standard Model need not have a homogeneous local profile. Scattering on macroscopic bodies can distort the field configuration near Earth and, for sufficiently large couplings, the atmosphere acts as an efficient shield. I will discuss this effect in the context of clock searches and show that space-based platforms offer a natural way around it. When the orbital altitude exceeds the dark-matter de Broglie wavelength, the orbit-averaged field amplitude is restored to its unscattered value.

In addition, for $m_{\rm DM} \gtrsim 10^{-10}\,\mathrm{eV}$, when the de Broglie wavelength becomes shorter than Earth’s radius, the dark-matter profile near Earth develops a dipole structure. For clocks in low Earth orbit, this produces a characteristic temporal modulation that can enhance sensitivity and provide a nontrivial cross-check of the signal interpretation. I will show that optical clocks on the ISS can set leading bounds in some regimes, and that future orbiting nuclear clocks could extend the reach further into parameter space inaccessible to ground-based searches.

Speaker: Dawid Brzeminski

16:30 → 18:30 Dark Matter: Indirect Detection

16:30 Explanation of Galactic Center GeV Excess via Cosmic Ray-Dark Matter Scattering

In this work, we propose a novel mechanism for generating gamma rays from the Galactic Center by scattering cosmic-ray protons off dark matter in the Milky Way halo. Unlike conventional explanations based on dark matter annihilation, the photon signal in the inelastic dark matter model arises from subsequent decays of a heavier dark matter component produced by the up-scattering of a lighter component constituting the ambient dark matter. This framework provides an excellent fit to the observed Galactic Center gamma-ray excess for a range of viable model parameters. More broadly, this framework also applies to another scenario involving two mediators that produce similar phenomenology. This approach provides a new avenue for interpreting gamma-ray observations of the Galactic Center.

Speaker: Debopam Goswami (Department of Physics & Astronomy, Texas A&M University)

16:45 Stress-Testing the 20 GeV Excess

A 20 GeV excess in the Fermi LAT gamma-ray sky has recently been reported by Totani and interpreted as a potential signal of dark matter annihilation. We independently reproduce this excess and systematically test its robustness. We evaluate the excess across more than 200 diffuse emission models, vary the region of interest, and examine spatial residuals. We additionally show the excess does not match observations of the Galactic center and perform a spectral-fit analysis to characterize the excess's energy dependence. While we confirm that the excess is present and statistically significant, we find that it does not behave fully consistently with a dark matter interpretation: its spatial properties deviate from those expected for annihilating dark matter and it is sensitive to diffuse model choices. Our results motivate caution in interpreting this feature as a dark matter signal.

Speaker: Eve Schoen (UC Berkeley)

17:00 Enhanced Cosmic-Ray Antinuclei Fluxes with Dark Matter Annihilation into SUEPs

Standard Model (SM) hadronic parton showers initiated by secondary cosmic-ray production or dark matter (DM) annihilations robustly predict very low antinuclei yields and a strong additional suppression for heavier antinuclei. We show that an important exception can arise if DM annihilates into a confining dark sector that produces Soft Unclustered Energy Patterns (SUEPs). The hallmark of SUEPs is the emission of very large multiplicities of soft dark mesons ($\pi_D$), which can overcome the usual phase-space suppression of antinuclei formation in parton showers, provided that the dark mesons decay promptly into SM quarks, i.e. within a SM hadronization length.
We study several benchmark realizations and find that for DM masses $m_{\rm DM}\sim\mathcal{O}(10~\mathrm{TeV})$, dark meson masses $m_{\pi_D} \sim 400~\mathrm{GeV}$, $\pi_D$ dominantly decaying to $t\bar t$, and a SUEP temperature $T_{\rm SUEP}\simeq 0.1\,m_{\pi_D}$, DM annihilation into SUEPs can yield tens of antideuterons and a few antihelium--3 events at AMS-02 at kinetic energies of $\mathcal{O}(\mathrm{GeV}$/n) and a few antideuterons and antihelium-3 events in GAPS at energies below 0.5 GeV/n. A future confirmation of an antinuclei signal by the AMS-02 or GAPS experiments could provide hints for hidden confining dynamics and would significantly constrain the relevant SUEP parameters.

Speaker: Caleb Gemmell (University of Wisconsin - Madison)

17:15 X-rays from Inelastic Dark Matter Freeze-in

Inelastic dark matter (iDM) consists of two almost mass-degenerate states with a small mass splitting and has been widely studied for its unique phenomenology. We consider iDM with a light dark photon/lepton-specific scalar mediator which feebly couples to the Standard Model particles. iDM is produced by freeze-in: the couplings are too small to put iDM in chemical equilibrium but can still gradually generate it to the observed abundance. Since the mediator is lighter than iDM, the coupling for DM abundance directly relates to the decay rate of the heavier state. The mass-splitting smaller than two electron masses and feeble couplings make the heavier state cosmologically long-lived. The suppressed decay of the heavier state emits three/two photons, which can be detected by an X-ray telescope. We conduct the Bayesian analysis of the 16-year data from the spectrometer onboard the INTEGRAL telescope using python-based platform 3ML; we then set the limits for the coupling of 100-MeV scale dark photon/lepton-specific scalar mediator and GeV-scale iDM. The resulting constraints are complementary to those from the existing collider and beam dump experiments.

Speaker: Riku Mizuta (TRIUMF / University of British Columbia)

17:30 Joint Spatial–Spectral Gaussian Process Modeling of the Galactic Center Excess

The origin of the Fermi-LAT Galactic Center Excess (GCE)—dark matter annihilation or unresolved point sources—hinges on its spatial morphology, which is challenging to disentangle from uncertainties in Galactic diffuse emission. Standard template-fitting approaches typically assume a fixed morphology for the excess, limiting their ability to discriminate between competing interpretations and to robustly characterize uncertainties. We build on Ramirez et al. (2025), who introduced a Gaussian Process (GP) framework to flexibly reconstruct the GCE morphology with uncertainty quantification, but in a single energy band. We extend this approach to multiple energy bins (2–20 GeV) within 20° of the Galactic Center, using a GP correlation structure that links morphology across energies and exploits shared spatial information. Using synthetic data generated from three diffuse emission models (O, A, F), we validate that the method recovers the injected signal when the assumed model is correct. Under cross-model fits, performance remains broadly stable, though some degradation appears for certain components in the presence of mismodeling. These results illustrate the potential of an energy-resolved GP framework for morphological inference of the GCE, while highlighting limitations relevant for application to real data.

Speaker: Sam Huang (Rutgers-New Brunswick)

17:45 AXIS Can Access Dark Matter Decays

As one of NASA’s proposed Probe Explorers missions, the Advanced X-ray Imaging Satellite (AXIS) is designed to improve on the sensitivity and spatial resolution of the Chandra X-ray Observatory and XMM-Newton. AXIS is designed to deliver low-background, arcsecond imaging over a broad $0.3-10$ keV energy range, with an extensive grasp of $1.6\times10^6\textrm{ cm}^2\textrm{ arcmin}^2$ at 1 keV. These capabilities will enable AXIS to probe a new region of parameter space for decaying dark matter candidates such as axion-like particles (ALPs) and sterile neutrinos via X-ray line searches. We present an initial study of AXIS’s prospects for detecting such signals, finding potential lifetime sensitivities of order $\sim 10^{30}$ s in the keV range, surpassing current limits by one to two orders of magnitude.

Speaker: Nimrod Shapir (The University of Chicago)

18:00 Enhancing Cosmic-Ray Antinuclei Fluxes from Dark Matter using Baryon Number

Antideuterons and antihelium in cosmic rays are widely regarded as smoking-gun signatures of dark matter annihilation. The tentative AMS observations are therefore intriguing, but difficult to explain within conventional models, which predict negligible antihelium fluxes. We propose a class of scenarios in which dark matter annihilates into particles carrying baryon and lepton number. Their decays enhance antinucleon and antinucleus production, yielding order-of-magnitude increases in antideuteron and antihelium-3 fluxes. Motivated by Grand Unified Theories, this framework provides a simple and testable explanation for the AMS antinuclei candidates.

Speaker: Fabrizio Vassallo (University of Wisconsin-Madison)

18:15 BBN constraints on the hadronic annihilation of sub-GeV dark matter

Residual annihilation of sub-GeV mass thermal relic dark matter candidates during big bang nucleosynthesis (BBN) can impact its predictions of light element abundances. Focusing on candidates with velocity-suppressed annihilation channels, I will discuss how the hadronic injection of pions and kaons beyond freeze-out, and their subsequent interaction with protons and neutrons prior to the deuterium bottleneck, provides a sensitivity to annihilation that surpasses that of the cosmic microwave background (CMB) and indirect detection in the galaxy.

Speaker: Afif Omar

16:30 → 18:30 Electroweak: Session 4

16:30 Electroweak PDFs for future lepton colliders

At future high-energy colliders, such as a multi-TeV muon collider or the high-energy stages of a linear $e^+e^-$ collider, collinear radiation of electroweak gauge bosons becomes significant. In this regime, vector-boson fusion and vector-boson scattering processes play a pivotal role in phenomenological studies, exhibiting kinematic signatures distinct from traditional $s$-channel annihilation. Electroweak Parton Distribution Functions (EWPDFs) provide a robust framework to describe these interactions by resumming large collinear logarithms and enabling a partonic interpretation of the hard-scattering process. In this contribution, we present the current status of the EWPDF formalism's implementation within the Monte Carlo event generator WHIZARD. We demonstrate several applications of this framework and provide detailed comparisons with full fixed-order matrix element calculations. Our results emphasize the necessity of this formalism for the ongoing R&D and physics potential studies of future lepton colliders.

Speaker: Krzysztof Mekala

16:45 Single 2HDM Higgs Production at a Muon Collider

We study the productions of single heavy Higgs bosons in the Two-Higgs-Doublet Models (2HDMs) with an electroweak (EW) gauge boson at a multi-TeV muon collider. Particular attention is devoted to the production of the charged scalars. We find that the single production via the radiative return in the effective boson approximation and the associated productions are complementary to one another, giving identifiable signals in many scenarios. The distinguishability of different types of 2HDM will be discussed.

Speaker: Juhun Kwak

17:00 Electroweak Restoration: SMEFT and HEFT

Colliders continue to push our understanding of electroweak (EW) interactions to ever higher energies. At high energies ($E \gg m_W,\,m_Z,\,m_h$), the broken EW theory is expected to converge to the unbroken theory. This is the electroweak restoration regime. We investigate how linear and non-linear realizations of the EW symmetry can be probed by comparing the relative longitudinal diboson production rates: $q \bar{q}'\rightarrow V_LV'_L$ and $q \bar{q}'\rightarrow V_Lh$. For linear and non-linear physics beyond the Standard Model, we consider the Standard Model Effective Field Theory (SMEFT) and the Higgs Effective Field Theory (HEFT), respectively. We present a general analysis of these amplitudes in the SM, SMEFT, and HEFT, and investigate how the ratios of these different cross sections are sensitive to linear vs. non-linear realization EW symmetry breaking. We find that the ratios of $W^\pm_LZ_L$ and $W^\pm_L h$ rates are particularly theoretically clean since these are expected to converge to one for the SM and SMEFT but not necessarily HEFT. We provide current LHC sensitivities to probing the SMEFT vs. HEFT operators and project to the high luminosity LHC.

Speaker: Ishmam Mahbub (University of Minnesota Twin Cities)

17:15 A Busy Higgs Signal

Higgs final states are central targets in the search for physics beyond the Standard Model. In the conventional picture, $SU(2)$ symmetry together with the Goldstone equivalence theorem correlates Higgs and gauge-boson final states, implying comparable sensitivities in channels such as $hh$, $ZZ$, and $WW$ for heavy resonances. In this work, we identify a simple way to parametrically violate this expectation. We show that higher-order Higgs couplings can induce an electroweak-symmetry-breaking enhancement that selectively amplifies Higgs-rich final states, allowing them to become the leading discovery channels of new resonances. For scalar resonances, this can make di-Higgs the dominant bosonic signal, while for high operator dimension or high resonance mass, it also opens resonant tri-Higgs and four-Higgs channels as well-motivated search targets. The same underlying mechanism extends to heavy fermionic and vector resonances, where it can similarly enhance channels such as $ht$, $Zh$, and $\gamma h$. We present this framework in effective field theory, illustrate possible UV completions, and discuss its implications for collider searches.

Speaker: Peiran Li (University of Minnesota)

17:30 Probing light gauge bosons using the muon (g-2)

The anomalous magnetic moment of the muon, i.e. $(g-2)$, is one of the versatile and promising probes of new physics at the GeV scale, particularly for $Z'$ gauge bosons that couple to both leptons and quarks. Due to inputs from experiments, lattice QCD as well as theory collaborations, one can constrain such BSM theories using various combinations of these inputs. Based on this idea, in this talk, I will introduce two tests related to the $(g-2)$, and the Hadronic Vacuum Polarisation (HVP) contribution to (g-2), which provide two independent ways to constrain new physics. I will highlight some of the key field theoretic aspects of the tests, along with the differences in the $( g-2)$ and HVP numbers from experiment, lattice and data-driven calculations, and their impact on these tests. I will then demonstrate their utility by applying them to two simple BSM extensions: the Dark Photon and the Baryon Number Gauge Boson. These tests could be used in a way akin to existing collider bounds (such as those from LHCb, BaBar etc)

Speaker: Kushan Panchal (University of Maryland, College park)

17:45 The Smallness of Polarization Interference in Weak Boson Production at the LHC

LHC data and phenomenological estimates agree that polarization interference is inherently small for multiboson production at the LHC. In this talk, we show that this could be understood from kinematical arguments and angular momentum conservation, and is a non-trivial consequence of the (near) masslessness of initial- and final-state fermions coupling to intermediate, helicity-polarized weak bosons. We finish we a brief comment on minor adjustments to search strategies can lead to more robust/stable definitions of polarization across different classes of gauge fixing.

Speaker: Richard Ruiz (Institute of Nuclear Physics (IFJ) PAN)

18:00 Multiboson Measurements at CMS

Measurements of processes involving multiboson final states constitute a precision test of the Standard Model. Moreover, discrepancies between theoretical predictions and experimental measurements could hint to new physics through the presence of anomalous gauge couplings. These processes are also dominant backgrounds for Higgs boson measurements, and searches for new particles with diboson final states. The most relevant and recent CMS measurements at 13 and 13.6 TeV will be presented.

Speaker: Cole Erik Kampa (Northwestern University (US))

18:15 -

16:30 → 18:30 Flavor Physics: Recent Developments

16:30 Parity solution to the strong CP problem in Pati-Salam models

We develop a universal seesaw Pati-Salam model which can solve the strong CP problem via parity symmetry. Realistic fermion masses can be generated with the introduction of vector-like fermions belonging to (1,1,15) and (1,1,10) of the gauge group $SU(2)_L \times SU(2)_R \times SU(4)_c$, while keeping the Higgs sector very minimal. Loop-induced corrections to $\overline{\theta}$ are estimated and shown to be consistent with neutron electric dipole moment limits. Based on the paper ``Universal Seesaw Pati-Salam Model with P for Strong CP,'' K.S. Babu and Sumit Biswas, [arXiv:2512.25028 [hep-ph]].

Speaker: Kaladi Babu

16:45 MaRTIn and four-loop operator mixing

I present the results of our calculation of the NNNLO QCD corrections to the mixing of flavor-changing current-current operators. They are relevant for the precision SM prediction of CP violation in neutral kaon mixing. Using this example, I will introduce our public code MaRTIn that can be used for fully automated multi-loop calculations.

Speaker: Joachim Brod (University of Cincinnati)

17:00 Portals to newSU(3) exotics-:he lepton-gluon and lepton-quark portals

Using Light exotics Effective field theory I explore new phenomenological portals to exotic color-charged particles. This talk focuses on portals where new exotic states can be accessed in events that involve one SM quark and lepton, or one Standard model gluon and lepton. The exotica found through this portal go beyond standard lepto-quark or lepto-gluon states and reveal states of large color representation, extremely exotic color octets, particles with higher lepton/baryon number and more. I explore such exotic particle production at LHC and future colliders.

Speaker: Linda Carpenter

17:15 Searches for vector-like fermions and leptoquarks with the ATLAS detector

The Standard Model of particle physics explains many natural phenomena yet remains incomplete. Leptoquarks (LQs) are hypothetical particles predicted to mediate interactions between quarks and leptons, bridging the gap between these two fundamental classes of particles. Vector-like quarks (VLQs) and vector-like leptons (VLLs) lie at the heart of many extensions seeking to address the Hierarchy Problem, as they can naturally cancel the mass divergence for the Higgs boson. This talk will present new results from LQ and VLQ searches with the ATLAS detector using proton-proton collision datasets collected during Run2 and Run3 at the LHC.

Speaker: Tomoya Iizawa (University of Tokyo (JP))

17:30 One Sum To Rule Them All

In this talk I will present a universal second-order $U$-spin master rate sum rule among the CKM-free Cabibbo-favored (CF), doubly Cabibbo-suppressed (DCS), and singly Cabibbo-suppressed (SCS) decay rates of weak charm decays in the Standard Model,
\begin{equation}
\frac{\text{sum of CF and DCS CKM-free rates}}{\text{sum of SCS CKM-free rates}} = 1\,,
\end{equation}
which holds up to second order in $U$-spin breaking. I will sketch the general group-theoretic construction underlying this relation and emphasize that, while the phenomenological application here is to charm decays, the construction itself is far more general. I will discuss the current status of this sum rule in charm systems. If time permits, I will also comment on possible extensions beyond charm and on broader directions toward understanding and applying higher-order flavor sum rules.

Speaker: Margarita Gavrilova (Caltech)

17:45 Production of B_c states in the Pythia parton shower.

Production of quarkonia states at colliders has been found to disagree with theoretical predictions in a number of ways, such as polarization and isolation. Recent developments in event generators have attempted to remedy these theoretical tensions via production of quarkonia in parton showers with an NRQCD model. In this work, we expand the NRQCD parton shower in Pythia to allow for different final-state quark flavors, meaning production of $B_c$ mesons in the parton shower. Comparisons with BcVegPy, a standalone Monte-Carlo generator for $B_c$ production, are made.

Speaker: Jake Pfaller (University of Cincinnati (US))

18:00 Protecting baryon number violating operators

Baryon number violation provides one of the most sensitive probes of physics beyond the Standard Model. Despite this sensitivity, baryon-number-violating effective operators of high mass dimension are generally suppressed compared to those of lower dimension. By studying UV completions of these operators, we identify many cases where certain UV completions generate operators only at or above a given mass dimension at tree level, requiring loop-induced diagrams to produce lower-dimensional operators, which in some instances are more suppressed than higher-dimension tree-level ones. Such scenarios can lead to higher-order operators becoming dominant. Additionally, we consider operators involving derivatives, which are often neglected in phenomenological analyses since they are typically suppressed relative to non-derivative operators. However, in cases where the lowest operator generated by a given UV completion necessarily involves a derivative, such operators can, in fact, become the dominant contributions.

Speaker: Diana Sokhashvili

18:15 Exotic Hidden-Heavy Hadrons and Where to Find Them

A new zoo consisting of dozens of heavy subatomic particles that contain more than three quarks and antiquarks have been discovered beginning in 2003.  Although they must be described by QCD, the pattern of these exotic heavy hadrons remained unexplained for more than 20 years.  I will present a simple proposal for the pattern based on the Born-Oppenheimer approximation for QCD.  This pattern could be corroborated by lattice QCD calculations of the spectrum of gluino hadrons (hadrons bound to a color-octet source). The existence of the isospin-0 hidden-charm tetraquark $\chi_{c1}(3872)$ implies that the lowest-energy gluino hadron has isospin 0 and $J^{PC} = 1^{- -}$. The pattern also explains a remarkable property of the isospin-1 hidden-bottom tetraquark $T_{c \bar c}(10650)$.

Speaker: Eric Braaten

16:30 → 18:30 New Physics at Future Colliders

16:30 SURFing to the Fundamental Limit of Jet Tagging

How close are modern jet taggers to the fundamental statistical limit of their task? Generative models with tractable likelihoods offer a route to this question: treated as surrogates for the data distribution, they enable the construction of Neyman-Pearson-optimal classifiers. The resulting bound, however, is only as reliable as the surrogate. In this talk, I introduce the SUrrogate ReFerence (SURF) method to test that reliability. SURF trains a candidate generative model on samples from a second, tractable surrogate and checks whether the candidate recovers the known optimal classifier of that reference. Applying SURF to top tagging, we find that different generative surrogates can yield substantially different estimates of the statistical limit, and identify specific models that fail this consistency test. I will discuss possible explanations and what this implies for interpreting existing claims about fundamental tagging limits.

Speaker: Ian Pang

16:45 Searches for New Resonances with CMS

The quest for new physics is a major aspect of the CMS experimental program. This includes models involving resonances that can decay to photons, leptons or jets. This talk presents an overview of such analyses with an emphasis on new results and the novel techniques developed by the CMS collaboration to boost the search sensitivity. The searches are carried out with data of the Run-II and Run-III of the LHC in proton-proton collisions with the CMS detector.

Speaker: Jeongeun Lee (Seoul National University (KR))

17:00 Testing the Robustness of Via Machinae Stellar Stream Candidates

We build upon the results of the Via Machinae algorithm for stellar stream-finding in Gaia data, employing new tests to identify the stream candidates most likely to represent real stellar streams. We measure the consistency with which candidates are discovered across multiple retrainings of the Via Machinae neural density estimators, and we find that classifying candidates based on this metric reduces the expected rate of false positive discoveries while increasing the number of stream candidates classified as real. As an independent test, we apply an automated orbit-fitting algorithm to determine whether each candidate lies along a physical orbit integrated in a model of the Milky Way gravitational potential. We present a list of candidates that pass both these tests and merit follow-up observations, some of which are to our knowledge previously unknown.

Speaker: Rafael Porto (Rutgers University)

17:15 Transforming Flavour Tagging with the ATLAS Detector: ML/AI tools and calibration techniques

The identification of jets containing b-hadrons is essential for many physics analyses at the LHC, including precision measurements of Higgs boson and top-quark processes, as well as searches for physics beyond the Standard Model. We present recent improvements in the discrimination of b-jets from jets originating from lighter quarks using the ATLAS detector. These advances are driven by state-of-the-art ML and AI techniques based on transformer architectures. Their performance is well modelled by the ATLAS simulation, as demonstrated through dedicated calibration studies, the results of which will be presented. Compared to previous algorithms, the transformer-based approach improves the rejection of c-jets (light-jets) by factors of 3.5 (1.8) at a b-jet tagging efficiency of 70%. We also discuss the latest version of this algorithm and its expected performance at the High-Luminosity LHC (HL-LHC).

Speaker: Storm Lin (Stony Brook University (US))

17:30 A Bi-adjoint Model from the W-Gluon Portal

This talk will briefly explore effective operator models where new light exotic (LEX) states interact with the Standard Model (SM) through the W-gluon portal. This portal allows access to LEX states with non-trivial representations under the SM gauge groups, and introduces new single production collider modes and phenomenological signatures at both the LHC and ep colliders. The talk will then look at the implications of adding a single new dimension five BSM operator to the SM Lagrangian. This simple operator, which contains a bi-adjoint scalar state in the (8, 3, 0) representation of the SM gauge groups, would require a new search at the LHC in order to reach a fairly significant discovery potential. I will outline some details of a potential search, and comment on the discovery potential of such a state.

Speaker: Katherine Schwind (The Ohio State University)

17:45 Opening the GeV Window at the LHC

In this talk, I present a newly proposed search strategy for GeV-scale particles that couple predominantly to light quarks at the LHC. Such models have often been assumed to be experimentally indistinguishable from QCD jets. We demonstrate that this is not the case: these particles can be perturbatively produced at the LHC and promptly decay into only a few hadrons, giving rise to jets with anomalously low charged-track multiplicity and mass. I will also discuss possible improvements that can be made for HL-LHC.

Speaker: Carlos Henrique de Lima (TRIUMF)

18:00 Heavy Vector Triplets at the Muon Collider

Heavy spin-one particles are well motivated new physics candidates that can have their origin in weakly coupled extensions of the Standard Model gauge group or in strongly coupled Composite Higgs models. Due to the variety of production and decay modes, Heavy Vector Triplets (HVT) are a useful benchmark for the study and comparison of future colliders. The Muon Collider is particularly suited for this search: I will present its potential of discovery in resonant and associated production, with leptonic or bosonic final states. Depending on coupling and channel, our differential likelihood analysis proves sensitive up to 5 times the centre of mass energy. We quantify the impact of the often neglected signal-background interference: HVT can have large decay width, making traditional analyses based on Narrow Width Approximation unviable. I will present simulation and analysis strategies applicable to all models featuring large widths.

Speaker: Francesca Acanfora (Umass Amherst)

18:15 Disentangling Multiple Light-Flavor Jets at Colliders

Providing a practical and hadron-level definition of multiple jet flavors is a long-standing problem in collider physics. Previous work has introduced a data-driven, operational definition of quark and gluon jets, but no generalization to multiple jet flavors presently exists. To address this, we introduce a practical machine-learning framework to extract any number of flavors from any number of data samples with minimal constraints. Intuitively, our procedure identifies the maximally separable categories in the data, also known as topics in the statistics literature. We demonstrate that our procedure infers the truth-level fractions of up-quark, down-quark, and gluon jets from various combinations of three samples. Then, we propose a tag-and-probe technique to extract multiple light flavors at colliders. Our findings show that the identifiability of jet flavors depends on their relative abundance in the samples and the hadron-level information available to the classifier architecture. Our work opens the door to searches for multiple jet flavors in experimental data, and it enables studies of the sample dependence of jet tagging.

Speaker: Gregorio de la Fuente Simarro (Massachusetts Institute of Technology)

19:50 → 22:20 Banquet

Wednesday 13 May

08:00 → 08:45 Breakfast

08:45 → 10:30 Plenary: Wednesday Early

Convener: Patrick Huber

08:45 Highlights of Neutrino Physics

Speaker: Mark Ross-Lonergan

09:20 Neutrino Physics Phenomenology

Speaker: Matheus Hostert (University of Iowa)

09:55 AI & ML for Particle Physics

Speaker: Konstantin Matchev (University of Alabama (US))

10:30 → 11:00 Coffee Break

11:00 → 12:45 Plenary: Wednesday Late

Convener: Prof. Keith Dienes (University of Arizona)

11:00 Strong CP Problem and the Physics with Axions