Particle Physics on the Plains​ 2025

15 Nov 2025, 08:00 → 16 Nov 2025, 17:05 US/Central

2048 Malott Hall (University of Kansas)

Particle Physics on the Plains will be held on November 15-16, 2025, at the University of Kansas. The workshop facilitates a discussion about the latest results in particle phenomenology and theory among  particle theorists in the region.  The format will be in person.

Talks are intended to be mostly student/postdoc talks.  If there is room in the schedule, we will add faculty talks. Nevertheless, this is an excellent opportunity for faculty to keep up on research in the region and gather for lengthy discussions.

Abstract, student/postdoc lodging deadline: October 22, 2025  There are funds available to help support lodging for students and postdocs who give talks. To be eligible for these funds students/postdocs must register and submit a talk abstract by 11:59 pm CST October 22, 2025.  Preference will be given to regional theoretical particle physics students/postdocs. However, provided funds are available, we will support the lodging of additional students/postdocs. Further details are on the registration and lodging pages. To obtain lodging, abstracts and registration must be submitted by this date.

November 8, 2025 Registration for all participants closes at 11:59 CST.

COVID-19:  Information about COVID-19 regulations at KU can be found here: https://protect.ku.edu/

Lunch on Saturday and coffee breaks will be provided during the conference.

This workshop is supported in part by the Research Excellence Initiative of the College of Liberal Arts and Sciences at the University of Kansas, the University of Kansas Office of Research, and the University of Kansas Department of Physics & Astronomy.

Previous year's website:  2017, 2018, 2019, 2022 (Part 1), 2022 (Part 2), 2023, 2024

Organizers: Terrance Figy, KC Kong, Ian Lewis (chair), Douglas McKay, John Ralston

 

Roommates.pdf

Saturday 15 November

08:00 → 08:50 Registration

08:50 → 10:15 Dark Matter

Convener: Prof. Jong-Chul Park (Chungnam National University (KR))

08:50 Conference Logistics/Information

Conference Logistics/Information

Speaker: Ian Lewis (The University of Kansas)

PPP_2025.pdf

09:00 Shedding Light on the KM3NeT Event: A Dark Matter Effect

The recent KM3NeT observation of an ${\cal O}(100~{\rm PeV})$ event KM3-230213A is puzzling because IceCube with much larger effective area times exposure has not found any such events. We propose a novel solution to this conundrum in terms of dark matter (DM) scattering in the Earth's crust. We show that intermediate dark-sector particles that decay into muons are copiously produced when high-energy ($\sim100~\text{PeV}$) DM propagates through a sufficient amount of Earth overburden. The same interactions responsible for DM scattering in Earth also source the boosted DM flux from a high-luminosity blazar. We address the non-observation of similar events at IceCube via two examples of weakly coupled long-lived dark sector scenarios that satisfy all existing constraints. We calculate the corresponding dark sector cross sections, lifetimes and blazar luminosities required to yield one event at KM3NeT, and also predict the number of IceCube events for these parameters that can be tested very soon. Our proposed DM explanation of the event can also be distinguished from a neutrino-induced event in future high-energy neutrino flavor analyses, large-scale DM direct detection experiments, as well as at future colliders.

Speaker: Ankur Verma

PPP_Ankur.pdf

PPP_Ankur.pdf

PPP_Ankur.pptx

09:18 Supernova-Boosted Dark Matter at Large-Volume Neutrino Detectors

Core-collapse supernovae, among the universe's most energetic events, offer a novel window into the dark sector by potentially producing a flux of boosted dark matter (BDM). We explore the potential to detect the BDM produced by supernovae with a focus on fermionic dark matter that interacts with the visible sector through a dark gauge boson. Our results indicate that major current and future large-volume neutrino detectors DUNE, Hyper-Kamiokande, and JUNO can significantly constrain or discover BDM within compelling parameter spaces, with sensitivity notably enhanced during nearby supernova occurrences.

Speaker: Badal Bhalla (University of Oklahoma)

SNBDM.pdf

09:36 Testing the dark side of neutrino oscillations with the solar neutrino fog at Dark Matter experiments

The recent detection of the solar neutrino background at Dark Matter direct detection experiments paves the way to fully explore an important degeneracy in neutrino oscillations in the presence of new interactions, named the LMA-Dark degeneracy. This degeneracy makes it impossible to determine the neutrino mass ordering in oscillation experiments if neutrinos have new vectorial interactions with matter. As the composition of solar neutrinos at the Earth consists of all three neutrino flavors, testing the presence of new neutrino interactions in the muon and tau neutrino sector in scatterings can fully probe the LMA-Dark region for the first time. In this paper we show that current data from XENONnT and PandaX-4T does not yet exclude the LMA-Dark region with equal couplings of a new mediator to muon and tau neutrinos and quarks, and we identify the possible experimental scenarios to do so in the future. We also show that Dark Matter experiments can distinguish new interactions in the muon or tau sector only from new interactions affecting both sectors.

Speaker: Tanmay Kushwaha (Colorado State University)

PPPKansas2025.pdf

09:55 Dark matter boosted by terrestrial collisions

Inelastic dark matter (IDM) models feature an energy threshold for scattering with Standard Model particles, which enables their consistency with the increasingly stringent limits placed by direct detection experiments. In a typical construction, elastic scattering is absent at tree level, and a lighter dark matter state must first upscatter into a heavier state in order to interact with the nuclei in the detector. We model the excitation of IDM in the Earth followed by its downscattering inside a detector, and we show that considering this process markedly enhances the sensitivity of existing detectors. In particular, current limits based on XENON100 and XENON1T data can be extended to significantly larger mass splittings.

Speaker: Christopher Cappiello

PPP 2025 Inelastic Dark Matter-2.pdf

10:15 → 10:45 Coffee Break

10:45 → 12:30 Collider

Convener: Bhupal Dev (Washington University in St. Louis)

10:45 Welcome

Conference welcome

Speaker: Ian Lewis (The University of Kansas)

10:55 What's New at the Physical Review

I will briefly discuss the Physical Review journals and the American Physical Society, including the current state of the journals and updates on some of our policies.

Speaker: Joshua Sayre

PPP2025.pdf

11:05 Axion-Mediated Dark Matter: Models and Future Experimental Opportunities

Dark matter (DM) remains one of the most profound mysteries in fundamental physics, motivating a wide array of theoretical models and experimental searches. Axions or axion-like-particles are theoretically well-motivated as they generically arise in models with a spontaneously broken global symmetry. They could either be good DM candidates or mediate the interactions between DM and the Standard Model. In this talk, we will give an overview of such DM models and highlight novel ideas to probe them using future laboratory-based experiments. Particularly, we will highlight ongoing experimental efforts on future fixed target experiments and DM direct detection experiments that will have access to large swaths of unexplored parameter space.

Speaker: stefania gori (UC Santa Cruz)

TalkKansas.pdf

11:35 A Baryon and Lepton Number Violation Model Testable at the LHC

We construct an explicit example of such a model which violates baryon number by one unit, $\Delta \text{B} = -1$, and lepton number by three units, $\Delta \text{L} = -3$, and show that despite stringent limits on the predicted $p \rightarrow e^{+}/\mu^{+} \overline{\nu}\overline{\nu}$ mode from the Super-Kamiokande experiment, the masses of the newly introduced elementary particles can be $\mathcal{O}$(TeV). We identify interesting unique signatures of baryon number violation of this model that can be probed both with currently available LHC data and with the upcoming High-Luminosity LHC. We also present a scenario for low-scale baryogenesis within the framework of this model.

Speaker: Dr Deepak Sathyan

BNV PPP.pdf

11:53 Searches for Supersymmetry with Compressed Scenarios

Results from the CMS experiment are presented for supersymmetry searches targeting so-called compressed spectra, with small mass splittings between the different supersymmetric partners. Such a spectrum presents unique experimental challenges. This talk describes the new techniques utilized by CMS to address such difficult scenarios and presents results based on these techniques.

Speaker: Justin Anguiano (The University of Kansas (US))

PPP2025_CompressedSUSY.pdf

12:11 Heavy QCD Axions at High-Energy Muon Colliders

We study the physics potential of heavy QCD axions at high-energy muon colliders. Unlike typical axion-like particles, heavy QCD axions solve the strong CP problem with phenomenology driven by the anomalous gluon ($aG\widetilde G$) couplings. Several ultraviolet scenarios are presented in which QCD axions with TeV-scale masses and decay constants arise consistently with a solution to both the strong CP problem and the axion quality problem. We perform a detailed collider analysis for both a 3 and 10~TeV muon collider, focusing on hadronic axion decays that gives rise to a dijet-resonance signature. Our projections for the axion discovery reach in the multi-TeV mass range demonstrate that a muon collider can significantly extend sensitivity to heavy QCD axions compared to existing experiments.

Speaker: Peiran Li (University of Minnesota)

axion_muc_kansas.pdf

12:30 → 14:00 Lunch

14:00 → 15:30 Neutrinos

Convener: Matheus Hostert (University of Iowa)

14:00 Decoupling Neutrino Magnetic Moment from Mass with $SU(2)_L$ Invariance

Standard Model extensions that yield observable neutrino magnetic moments typically also induce large neutrino masses, incompatible with experimental limits.
This tension motivates the search for mechanisms that naturally decouple magnetic moments from mass generation without requiring fine-tuning.
In this talk, I propose a novel mechanism for generating Dirac and Majorana neutrino magnetic moment, in which the associated mass contribution is forbidden by $SU(2)_L$ invariance.
By carefully selecting the $SU(2)_L$ representations connecting the neutrino to the loop diagram, we ensure that only the effective dipole operator involving the non-Abelian part of the photon --- the neutral $SU(2)_L$ gauge boson --- is generated. Crucially, the corresponding mass diagram, obtained by removing the external gauge boson leg, vanishes.
I will also provide explicit UV completions that implement this mechanism and yield neutrino magnetic moments within the sensitivity of current and future experiments.

Speaker: Anil Thapa (Colorado State University)

NMM_PPP_thapa.pdf

14:18 Connecting pseudo-Nambu–Goldstone dark matter and pseudo-Dirac neutrinos through left–right symmetry

We explore a left–right symmetric model in which both neutrino masses and dark matter stability have a common origin. The dark matter is identified as a pseudo-Nambu–Goldstone boson (pNGB). Its scattering with nucleons is naturally suppressed. At the same time, neutrinos here are pseudo-Dirac particles with Dirac masses generated at the two-loop level. Small Majorana mass terms arise from Planck-scale effects, leading to tiny active–sterile mass splittings. The framework simultaneously provides a parity solution to the strong CP problem without an axion and predicts an interesting connection between the dark-matter lifetime and the neutrino mass-splitting.

Speaker: Mr Sumit Biswas (Student)

PPP_2025_two_pseudos.pdf

14:36 Probing Neutrino Mass Models with Tau Appearance at IceCube

Neutrino mixing parameters receive quantum corrections and therefore evolve with energy. A mismatch between the mixing parameters at the production and detection scales can produce measurable effects in flavor transitions. We investigate an ultraviolet-complete model of neutrino mass that predicts an observable running of the mixing matrix. We evaluate the IceCube sensitivity to this effect, focusing on TeV-scale muon-to-tau neutrino oscillations, which are strongly suppressed in the standard framework. The observation of an excess in tau appearance would provide a clear signature of a running mixing matrix.

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

running_PPP25.pdf

14:54 Probing scalar non-standard interaction of supernova neutrinos in next-generation neutrino experiments

A new neutrino-matter interaction can potentially affect neutrino propagation through matter. In this work, we explore the impact of a flavor-conserving scalar-mediated non-standard neutrino interaction in the supernova neutrino flux. We observe that the presence of scalar interaction involving muon and tau neutrinos (parameterized as $\eta_{\mu\mu}$ and $\eta_{\tau\tau}$, respectively) can invert the neutrino mass eigenstate in which three neutrino flavor states are produced inside the Supernova core, resulting in a significant modification of the electron neutrino flux from supernova reaching the Earth. In the context of the DUNE experiment, we estimate the number of supernova neutrino events in the presence of scalar non-standard neutrino interaction $\eta_{\mu\mu}$ or $\eta_{\tau\tau}$ and contrast with the case without scalar-mediated non-standard interactions. Our results indicate that such scalar interactions introduce a new degeneracy in the measurement of neutrino mass ordering from supernova neutrinos. We show how the $\bar{\nu}_e$ event distribution in Hyper-Kamiokande experiment can help resolve the degeneracy between a model with new scalar interactions for normal ordered neutrino masses and the standard model with inverted mass ordering.

Speaker: Sudipta Das (University of Iowa)

SNe-SNSI-PPP.pdf

15:12 CHARGED-PION CROSS-SECTION MEASUREMENT1FROM NOvA

The NuMI Off-Axis Appearance $\nu_e$ (NOvA) experiment is designed to study neutrinos and their interaction properties with matter. NOvA is a long-baseline neutrino oscillation experiment consisting of a Near Detector at Fermilab and a Far Detector in Ash River, Minnesota. Its primary goals are to determine the neutrino mass hierarchy and constrain the charge-parity (CP) violation phase. In addition to oscillation measurements, the NOvA Near Detector provides an ideal sample for measuring neutrino-nucleus interaction cross sections, which are crucial for reducing uncertainties in oscillation analyses. This analysis aims to minimize systematic uncertainties. Here, we present the status of an analysis that uses data from the NuMI beam, which peaks at 1.8 GeV in neutrino energy, to measure the cross section of the interaction $ν_\mu+N→\mu^\pm+\pi^\pm +nX$ as a function of muon and leading-pion kinematics, where $\pi^\pm$ represents any number of charged pions, and $nX$ denotes any particles in the final state. This analysis is sensitive to both deep inelastic scattering and resonance processes.

Speaker: palash kumer roy (Wichita State University)

charged_pion_ku-plain-final_v.pdf

charged_pion_ku-plain-final_v.pptx

15:30 → 16:00 Coffee Break

16:00 → 17:33 Astroparticle

Convener: Kuver Sinha (University of Oklahoma)

16:00 New Constraints on Dark Matter from Cosmic Rays and Stars

We explore novel astrophysical probes of Dark Matter in the dense spike environments surrounding supermassive black holes. First, we analyze the effects of elastic DM scattering with protons and electrons on the energy budget of observed stars near Sagittarius A*. By suppressing or enhancing their luminosity, we derive constraints on DM-electron and DM-proton cross sections. These constraints apply robustly across a broad DM mass range and halo profile assumptions, offering complementary sensitivity to parameter space relevant for freeze-in production and cosmic-ray boosted DM. Second, we introduce a method leveraging the survivability of ultra-high-energy cosmic rays accelerated near supermassive black holes: large DM–nucleon cross sections would fragment heavy nuclei, preventing them from reaching observed energies. Applying acceleration requirements, we set stringent bounds on DM–proton interactions for DM masses between 100 keV and 1 GeV. Together, these approaches highlight the potential of extreme astrophysical environments to place competitive and complementary constraints on dark matter interactions beyond current terrestrial and cosmological limits.

Speaker: Stephan Meighen-Berger (University of Iowa)

SMB_PPP_2025.pdf

16:18 New Gamma-Ray Constraints on Light CP-even Scalar from SN1987A

A light CP-even scalar singlet $S$ mixing with the Standard Model (SM) Higgs boson can be produced abundantly in hot and dense astrophysical environments such as the supernova core via nucleon bremsstrahlung process $NN \to NNS$. We reevaluate the production rate of $S$ and its subsequent decay and reabsorption in the supernova core. We then consider secondary photons from the scalar decay $S \to e^+ e^-$, which could give rise to an observable gamma-ray signal. We subsequently use the gamma-ray limits from SN 1987A based on the Solar Maximum Mission data to place new constraints on the mixing of the scalar $S$ with the SM Higgs boson. These gamma-ray constraints cover substantially new parameter space in the scalar mass-mixing plane, compared to the existing limits.

Speaker: Yue Yu (Washington University in St. Louis)

PPPYue.pdf

16:36 Energy Loss in Cepheids: Axions, Millicharged Particles, and Blue Loops

I will talk about the inclusion of axions and millicharge particles (MCPs) in stellar evolution. Axions are considered a promising candidate for dark matter due to their small mass and the potential for large-scale production in stellar environments, which can significantly affect stellar evolution. A similar argument can be said with the inclusion of MCPs in stars. Cepheid variables are particularly sensitive to axion or MCP production, as it may eliminate evolutionary stages of Cepheids. This alteration effectively removes the blue loop phase of Cepheids, leading to constraints on the axion photon coupling $g_{10}$ and MCP fractional charge $\epsilon_{\chi}$.To investigate this, we simulate a grid of models using MESA ranging from 4-12$M_{\odot}$ varying convective overshoot, rotation, $g_{10}$, and $\epsilon_{\chi}$. We compare our models to observations of s Musaca and Su Cygni. We find that including more massive Cepheids leads to stronger bounds.

Speaker: Thomas Gehrman (University of Oklahoma)

PPP2025_Thomas_Gehrman.pdf

16:54 Constraints on Heavy Axion-like Particles from Gamma-Ray Bursts

Gamma ray bursts (GRBs) are one of the most luminous astrophysical sources that can copiously produce axion like particles (ALPs). We delineate the uncertainties in ALP production in the relativistic jets surrounding GRBs. Under conservative assumptions, we find the ALPs produced in the jets can escape and subsequently decay. We show that the decay of axions can produce a secondary fireball for masses $m_a\sim 100$MeV and $g_{a\gamma}\sim 10^{-10}\text{GeV}^{-1}$ that can have observable astrophysical signatures.

Speaker: Saurav Das (Washington University in St. Louis)

Das_PPP.pdf

17:12 Unveiling Axion-like particles through Eclipsing Neutron Stars

Interaction between axion-like particles (ALPs) and photons can allow photons to oscillate into ALPs and pass through otherwise opaque regions. This effect is the basis of the light-shining-through-walls experiments. In this talk, I will show that such an approach can be successfully realized at astrophysical length scales using eclipsing neutron stars. During an eclipse, photon flux can partially convert into ALPs near the neutron star, traverse the companion star, and reconvert back into photons in the magnetic field of the interstellar medium. By analyzing the flux during eclipse and comparing it to the out-of-eclipse counterpart, we can put constraints on the ALP-photon coupling using this novel technique. We find that the eclipsing high mass X-ray binary, LMC X-4, is particularly well-suited for our purpose. Our results suggest that for ALPs with masses $m_a \lesssim 10^{-11}$ eV, coupling strengths as low as $g_{a\gamma} \lesssim (10^{-10} - 10^{-11}) GeV^{-1}$ could be probed. In summary, I will highlight the potential of eclipsing neutron stars as astrophysical laboratories for ALP searches.

Speaker: Dibya S. Chattopadhyay (Oklahoma State University)

Eclipse_ALPs_Kansas_Dibya.pdf

Sunday 16 November

08:30 → 09:00 Registration

09:00 → 10:30 Parallel 1: Neutrinos

Convener: Doojin Kim

09:00 Searching for BSM solar neutrino interactions using directional detectors

In this talk, I explore the potential of future small-scale gas TPCs with directional ability to probe neutrino interactions beyond the standard model. Working in the framework of non-standard neutrino interactions (NSI), we calculate combined energy-angle distributions of electron and nucleus recoils by solar neutrinos to place constraints on NSI parameters. We estimate that with realistic background reduction, a 30$m^3$ detector could reach sensitivities comparable to Borexino.

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

Presentation.pdf

09:18 Quantifying the Nuclear Form Factor Uncertainties on the Neutrino Trident Events at Short-Baseline Neutrino Experiments

We present the first detailed analysis of nuclear form factor uncertainties relevant for neutrino trident processes at argon-based short-baseline neutrino detectors. Accurately quantifying this uncertainty is important to perform precision Standard Model physics analyses and Beyond the Standard Model searches using neutrino tridents of all flavors, a feat which will be possible for the first time with future neutrino experiments like DUNE. Previously, such uncertainties were estimated to be $\sim 1\%$. Our work shows that the uncertainties can be as high as $\sim 10\%$ depending on the choice of parametrization, leading to a significant variation in the number of expected events. We present our results for several form factor parameterizations and discuss their impact on the experimental sensitivities. We also briefly assess the effect on the proposed FLArE experiment.

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

Presentation.pdf

09:36 Distinguishing Flavor Model Predictions at Neutrino Experiments

Probing flavor models which provide a rationale behind the observed pattern of neutrino mixings can bring us closer to understanding the origin of flavor in the Standard Model of particle physics. The most predictive flavor models predict not only the mixing parameters but also correlations between them. We study several classes of flavor models, contrast their predictions with current neutrino data, and answer the question if and how one can distinguish between different models at upcoming neutrino oscillation and neutrino mass experiments.

Speaker: Henry Truelson (Colorado State University)

PPP_PresentationTruelson2025.pptx

09:54 Neutron Star Mergers as a Probe of Neutrino Mass via Gravitational Wave and Neutrino Timing

Next-generation neutrino experiment Hyper-Kamiokande is expected to detect the diffuse supernova neutrino background (DSNB) over a decade-long observation. While supernovae have received considerable attention, binary neutron star (BNS) mergers represent a complementary, yet largely unexplored, diffuse neutrino source. The landmark multi-messenger detection of GW170817 demonstrated the potential of combining gravitational waves and gamma-rays to probe physics at cosmological distances. Motivated by such multi-messenger observation, we study neutrinos from BNS mergers and show that Hyper-Kamiokande could detect approximately one neutrino event from BNS mergers over 10-20 years of operation, depending on the mergers profile and luminosity models. We demonstrate that such events can be confidently associated with their progenitor mergers using time correlation from advanced gravitational-wave detectors and a neutrino detector, with minimal risk of misidentification against DSNB backgrounds. Further, upon identifying a neutrino event from a neutron star merger, the relative timing between the neutrino and gravitational-wave signals will allow us to place constraints on the neutrino mass. We perform simulations that incorporate relevant uncertainties, including those corresponding to the neutrino emission time and the location of the merger, and find that the resulting sensitivity to the lightest neutrino mass surpasses both the strongest terrestrial bounds from KATRIN and astrophysical projections from galactic supernovae, where the latter are limited by much shorter baselines compared to the typical distances of binary neutron star mergers. Additionally, we extend this analysis to constrain the graviton mass and its velocity dispersion, finding projected limits significantly stronger than current laboratory bounds.

Speaker: Tousif Raza

Tousif_talk_Kansas_2025.pdf

10:12 Neutrino Production and Detection in Muon Collider Acceleration

We study the neutrino flux at the accelerator stages of a future muon collider by simulating a hydrogen gas detector at a fixed location down the beamline. We investigated the event rate and energy spectra of neutrinos produced by the muons decaying in the accelerators. By comparing the resulting neutrino energy scales and interaction rates with those expected from existing neutrino factory concepts, we evaluated the viability of using muon collider accelerators as high-energy neutrino sources.

Speaker: Ju-Yeol Choi (University of Iowa)

neutrino_production_muC.pdf

09:00 → 10:30 Parallel 2: Model Building

Conveners: Peisi Huang, Peisi Huang

09:00 A path to leptoquark aided leptogenesis

Seesaw models of neutrino masses and leptogenesis are oft accompanied by LeptoQuarks (LQs) in various top down UV completions like Pati-Salam and $SO(10)$ and consider their impact on thermal leptogenesis. We demonstrate a minimal possibility of achieving successful leptogenesis with just an additional $(3,2,\frac{1}{6})$ "doublet leptoquark" to the standard two Right Handed Neutrinos (RHNs) which significantly alters the standard scenario through additional CP asymmetry produced in their decays, additional scatterings of the leptoquark altering the abundance of the RHN and final lepton asymmetry. This opens up new possibilities to analyze the impact of general B-L violation, apart from the lepton number violating decays of the RHN in standard leptogenesis, thereby paving a way to understand further, the impact of "primordial" B-L asymmetry on leptogenesis.

Speaker: Sai Charan Chandrasekar (PhD Student at Oklahoma State University)

PPP_Kansas_2025.pdf

09:18 From Stringy Compactifications to Dark Universe: A "Two Birds, One Stone'' Approach

String compactifications generically predict the presence of light scalar moduli, whose late-time coherent oscillations and decay induce an early matter-dominated era, often in tension with constraints from Big Bang Nucleosynthesis (BBN) and Cosmic Microwave Background (CMB) observations. Their decay can both reheat the visible sector and populate hidden sectors, potentially contributing to the dark radiation abundance. In this work, we investigate scenarios where moduli decay into both Standard Model and hidden-sector particles occurs sufficiently early to avoid these conflicts, while simultaneously contributing to the dark radiation abundance, typically parameterized as extra relativistic degrees of freedom, ΔNeff​. We construct and solve a system of coupled Boltzmann equations describing modulus decay channels into visible and hidden sectors—particularly axions—and employ a phase-space–based numerical approach to compute the resulting ΔNeff with high precision which can be measured by upcoming CMB stage-4 measurements and any deviations can be detected. In effect, we try to solve Cosmological Moduli Problem as well as the stringent bounds on ΔNeff by one decay mechanism which we study in detail, lepton-photon axion interaction after modulus thermal decays into SM particles. Thus, choosing a unified approach to both longstanding problems and connecting ultraviolet string theory dynamics to precision cosmological probes.

Speaker: Aditi Shahani (University of Oklahoma)

KU-Aditi (1).key

KU-Aditi.key

KU-Aditi.pdf

09:36 Quark and Lepton Masses in Universal Seesaw Models with Modular A4 Symmetry

I will present a study of quark and lepton masses in a universal seesaw
with modular A4 symmetry. Light fermion masses arise from mixing with
heavy vector-like partners. A SUSY setup with gCP and minimal Z2 is
adopted in this model. The global fit uses 17 parameters in total—the
complex τ plus 15 real parameters—to describe 18 observed quantities
across the CKM and PMNS sectors. The fitted observables agree well with
current measurements, demonstrating that the model can account for both
CKM and PMNS patterns without extra flavons. This framework yields
predictions for the leptonic Dirac phase δCP, the two Majorana phases, the
effective neutrinoless double-beta mass mee, the lightest neutrino mass (in
normal ordering), and the sum of neutrino masses. The predicted values
fall within reach of current and near-future measurements, making the
framework directly testable in 0νββ searches.

Speaker: Murshed Alam (Oklahoma State University)

Murshed_Presentation_Kansas'25.pdf

09:54 Investigating Higgs Coupling Modifications in Vector Boson Fusion Higgs Pair Production.

Understanding how the Higgs boson interacts with itself and with other particles remains one of the central goals of particle physics. In this project, I investigate Higgs boson pair production through the vector boson fusion (VBF HH) process to explore possible deviations from the Standard Model. Using Herwig and VBFNLO event generators, I simulate proton–proton collisions and study how varying these coupling modifiers, κ_V, κ_2V, and κ_λ, affects the event rates and kinematic distributions. Each parameter is varied independently while applying standard VBF cuts, including minimum jet transverse momentum, rapidity gap, and dijet invariant mass requirements. We anticipate that the preliminary results will inform us about the unique contributions of each of the coupling modifiers, k-parameters. These findings will demonstrate how VBF HH production can serve as a sensitive probe of the Higgs sector and help guide future efforts to search for new physics beyond the Standard Model.

Speaker: Tunde Kushimo (Wichita State University)

Tunde_Kushimo_PPP_2025.pdf

10:12 Sterile Neutrino Dark Matter Production via Active–Sterile Non-Standard Interactions

Sterile neutrinos are compelling dark matter candidates, but production solely from active-sterile oscillations is excluded by astrophysical observations. Non-standard self-interactions in either active or sterile sector can modify production to some extent. Here we propose a novel solution where scalar-mediated non-standard interactions between active and sterile neutrinos generate new production channels for $\nu_s$, independent of the active-sterile mixing and without the need for any fine-tuned resonance or primordial lepton asymmetry. Focusing on the heavy-mediator regime ($m_\phi \gtrsim 5\,\mathrm{GeV}$), these interactions efficiently populate the sterile sector even for vanishingly small mixing, while remaining consistent with cosmology and structure-formation bounds. The mechanism broadens the viable parameter space relative to scenarios that rely on mixing and implies potentially observable neutrino-dark matter interactions in astrophysical environments.

Speaker: Aaroodd UR

PPP2025_Aaroodd.pdf

10:30 → 11:00 Coffee Break

11:00 → 13:00 Quantum/Gravity Wave/Phase Transitions

Convener: Dorival Gonçalves (Oklahoma State University)

11:00 Quantum Sensing and Radiative Decay

A novel strategy for detecting radiative decay of very weakly interacting particles is explored by leveraging the extreme sensitivity of quantum devices, to faint electromagnetic signals. By modeling the effective electric field induced by the decay photons, the response of quantum sensors is evaluated across two particle physics scenarios: the cosmic neutrino background and two-component dark matter. We assess the discovery potential of these devices and outline the parameter space accessible under current experimental capabilities. Analysis demonstrates that quantum sensors can probe radiative decays of dark matter candidates using existing technology, while probing neutrino magnetic moments beyond current limits will require scalable quantum architectures with enhanced coherence.

Speaker: Miguel Angel Soto Alcaraz

QS.pdf

11:18 Helicity space entanglement in 2-2 scattering

Recent studies suggest that the symmetries underlying fundamental interactions may have a quantum-information–theoretic origin.By analyzing the relativistic S-matrix as a quantum logic gate acting on the bipartite Hilbert space, one can explicitly trace how Lagrangian-level symmetries are realized in the space of quantum states. In this work, we focus on the entanglement structure in the helicity space, in 2-2 scattering, and demonstrate how distinct symmetry patterns are encoded in the entanglement properties of the scattering states, providing deeper insights and connection between quantum-information and particle scatterings.

Speaker: Rahul Muraleedharan (University of Oklahoma)

Kansas_talk.pdf

11:36 Constraints on Symmetric Dark Matter from Neutron Star Capture and Collapse

Dark matter (DM) models with a conserved particle$-$antiparticle number, $n_\chi-n_{\tilde \chi}$, and the asymmetry in the cosmological abundance $n_\chi\neq n_{\tilde \chi}$, are known to be challenged by the existence of old neutron stars (NSs), as the sufficient accumulation of DM will lead to the collapse of NSs into black holes. We demonstrate that the applicability of these constraints is much wider and covers models with symmetric populations of DM, $n_\chi = n_{\tilde \chi}$, as the process of DM capture regulated by a nucleon-DM scattering can be inherently asymmetric, $\sigma_{\chi n}\neq \sigma_{\tilde\chi n}$. The asymmetry is induced by the interference of different types of $\chi$-$n$ interactions, provided that their combination is odd under charge conjugation in the DM sector, $C_\chi$, and even under combined parity $P_{\chi + n}$. We provide a complete analysis of DM-nucleon bilinear $\chi$-$n$ interactions and find that this asymmetry is very generic. Using canonical NS parameters and local DM halo inputs, we exclude spin-averaged scattering cross sections down to $\sigma_{n\chi}\!\gtrsim\!10^{-46}\,{\rm cm}^{2}$ at DM mass $m_\chi\!\lesssim\!10^{10}\,{\rm GeV}$ for the maximally asymmetric capture rate, and show that the constraints persist down to very small values of the cross-section asymmetry, ${\cal A}=(\sigma_{\chi n}- \sigma_{\tilde\chi n})/(\sigma_{\chi n}+ \sigma_{\tilde\chi n})\gtrsim 10^{-5}$.

Speaker: Yuxin Liu (International Centre for Theoretical Physics Asia-Pacific)

NS_for_Dark_Matter_PPP.pdf

11:54 Quantum Entanglement in Yang-Mills

We study the quantum entanglement in Yang-Mills theory. Due to the Color-Kinematic duality, the color and helicity parts are separable which enables the study of the quantum entanglement in color space and helicity space individually. In color space, we compute the quantum entanglement in the SU(2) and SU(3) gauge group and display the large N limit. The Dimension-six operators preserve this universality, while dimension-eight deformations populate new color sectors and shift entanglement , suggesting that entanglement in color space functions as a tomographic probe of effective operators. In the helicity space, we show that the final states always remain maximally entangled with the maximally entangled initial state. This is related to the MHV property of the YM scattering amplitude at tree level. Our results suggest that the information-theoretic viewpoint unifies algebraic, geometric, and dynamical aspects of scattering.

Speaker: Kunfeng Lyu

Entanglement_YM.pdf

12:12 Gravitational Waves from Phase Transitions in an Early Matter Dominated Epoch

We study how an early matter dominated (EMD) epoch affects the thermal history and first-order phase transitions (FOPT) in the early Universe. A heavy scalar with field-dependent decay width drives reheating, producing non-adiabatic cooling and heating phases. These transitions change the expansion of Universe, shaping the primordial gravitational wave (GW) spectra from FOPT, which can exhibit single or multiple peaks. Our analysis connects scalar properties such as mass and coupling to GW observables, showing how these parameters affect peak frequency and amplitude while remaining consistent with cosmological bounds, thereby offering a probe of beyond Standard Model physics through future GW detections.

Speaker: Fazlollah Hajkarim (University of Oklahoma)

GW-FOPT-Kansas-2025.pdf

12:30 Gravitational Waves and Primordial Black Holes in First-Order Phase Transitions

Many extensions to the Standard Model are expected to yield first-order phase transitions (FOPTs) which could produce detectable signals of gravitational waves (GWs) and observable abundances of primordial black holes (PBHs). We study such FOPTs within conformal $B-L$ models, which naturally accommodate stronger GW signals due to supercooling. By scanning large regions of parameter space, we compute GW spectra across symmetry breaking scales and find signals spanning the sensitivities of planned experiments including THIEA, LISA and aLIGO. We correlate these spectra with PBH abundances to identify viable multi-messenger benchmarks.

Whereas many analyses rely on approximate criteria for horizon formation or fixed density-contrast thresholds in determining PBH collapse, we employ a relativistic method originally developed by Blau, Guendelman, and Guth (1987). This approach maps the dynamics of false-vacuum remnants onto an effective one-dimensional potential, where the turning point marks the onset of collapse. Using this formalism, we obtain a reliable connection between microscopic particle physics and macroscopic PBH formation at a low computational cost. Together with the GW analysis, this framework provides a systematic and testable bridge between early-universe physics and present-day observations.

Speaker: Cash Hauptmann (University of Nebraska - Lincoln)

Hauptmann_PPP2025.pdf

13:00 → 13:30 Closing Remarks