UCLA Dark Matter 2025

24 Mar 2025, 07:30 → 27 Mar 2025, 18:45 US/Pacific

UCLA Physics and Astronomy Building 1-425

For information on the venue and accommodations, use the "UCLA Conference Website" link to the left or go to http://darkmatter2025.pa.ucla.edu.

For registration, please click on the "Registration" option on the left of this Indico page. After you register on this website, to pay for the registration and/or additional banquet tickets, please use the "Registration-Payment" link https://commerce.cashnet.com/DARKMATTER.

Please note that the early registration fee $600 will change on November 30, 2024, at 16:00 (4pm) Pacific Time into late registration fee $700. Registration closes on February 28, 2025 at 4PM Pacific Time. We encourage participants to register as early as possible to facilitate our planning.

Thanks to the generous support of Kudu (https://kudu.com/) we can offer a limited number of reduced registration fees for graduate students $400 instead of $600 for early registration. Interested students should have their advisor write a short email to darkmatter@physics.ucla.edu, explaining how the research fits within the scope of the conference, and why it is important for the student to attend. Be sure to include in the message a brief description of the proposed talk or poster, if applicable. Applicants that fit within the scope of the conference will be given an access code for the reduced registration fee, on a first come first served basis.

Monday 24 March

07:30 → 07:55 Registration

07:55 → 08:25 Welcome and Introduction

08:25 → 09:40 SESSION 1: Cosmology and structure formation

08:25 Is Dark Energy Evolving?

NA

Speaker: Josh Frieman

08:50 Dark matter physics from small-scale cosmic structure

NA

Speaker: Risa Wechsler

09:15 The Hubble Constant Problem

NA

Speaker: Lloyd Knox

09:40 → 10:10 Coffee Break

10:10 → 12:15 SESSION 2: Astrophysics and Indirect Dark Matter Searches

10:10 Dynamical astrophysical probes of dark matter

NA

Speaker: Jo Bovy

10:35 PaleoDetectors (Ancient Minerals from Deep Underground)

Paleo-detectors are a proposed experimental technique to search for dark matter (DM). In lieu of the conventional approach of operating a tonne-scale real-time detector to search for DM-induced nuclear recoils, paleo-detectors take advantage of small samples of naturally occurring rocks on Earth that have been deep underground (≳5 km), accumulating nuclear damage tracks from recoiling nuclei for (1) Gyr. Modern microscopy techniques promise the capability to read out nuclear damage tracks with nanometer resolution in macroscopic samples. Thanks to their (1) Gyr integration times, paleo-detectors could constitute nuclear recoil detectors with keV recoil energy thresholds and 100 kilotonne-yr exposures. This combination would allow paleo-detectors to probe DM-nucleon cross sections orders of magnitude below existing upper limits from conventional direct detection experiments. Paleodetectors have a variety of uses in addition to DM: as neutrino detectors, e.g. they may be used to ascertain the history of the past supernova rate in our Galaxy, to study cosmic rays, and for nuclear reactors.

Currently this field has become experimentally very active in a worldwide effort including the US, Germany, Japan, and others, with biannual meetings and plenty of funding: We received an NSF grant (based at VA Tech) for 3.5M dollars and Josh Spitz at University of Michigan received 1.5M dollars from the Moore Foundation.

Speaker: Prof. Katherine Freese (University of Texas)

11:00 Galaxies as Probes of the Particle Physics Nature of Dark Matter

NA

Speaker: Mariangela Lisanti

11:25 An overview of new dark matter constraints from strong gravitational lensing probes.

Strong gravitational lensing can provide direct insight into the nature of dark matter and the structures it forms on small scales. In a strong gravitational lens, multiple images of a background source appear due to deflection by foreground massive structures. In galaxy and cluster-scale strong gravitational lenses, low-mass perturbations due to small-scale structure such as low-mass dark matter halos can significantly distort and shift the lensed images providing direct insight into underlying matter distribution and thereby leading to novel constraints on the physical properties of dark matter. Analyses of strong gravitational lenses have yielded some of the strongest constraints to date on a range of dark matter models including fuzzy dark matter, primordial black hole dark matter, warm dark matter and self-interacting dark matter. I will give an overview of recent results in this field from teams using a variety of complementary techniques.

Speaker: Dr Anna Nierenberg

11:50 Probing ultra-light dark matter wave interference with astrophysical observations

In this talk, I will discuss the latest efforts to constrain the mass of the ultra-light dark matter models, focusing on the current bounds of the fuzzy dark matter (FDM) model. I will show how we can use the different predictions of this model and different astrophysical systems to put the strongest bounds to date on the mass of this ultra-light axion, also showing the incompatibilities currently present in these bounds. Particular focus will be given to the current developments in using interference patterns to probe the FDM model showing how strong lensing and pulsar timing arrays are powerful probes to measure this wave behaviour.

Speaker: Elisa Gouvea Mauricio Ferreira

12:15 → 13:15 Lunch Break

13:15 → 15:20 SESSION 3: Dark Matter Particle Candidates and Accelerator Searches

13:15 Dark Matter: Quo Vadis?

NA

Speaker: Hitoshi Murayama

13:40 Interferometers for dark matter and other new physics

NA

Speaker: Kathryn Zurek

14:05 What can solve the Strong CP Problem?

While the axion is the most popular solution to the strong CP problem, it is sometimes claimed that the strong CP problem can be solved by imposing parity or CP as a symmetry of the theory or perhaps to ignore the strong CP problem completely by fine tuning the theta angle. For these solutions to work, the theta angle has to be a parameter of the theory. I will argue that this is incorrect - the theta angle of QCD arises as a choice of quantum state and it is thus not a parameter that can either be set to zero by imposing a symmetry or fine-tuning. This shows that the strong CP problem can only be solved by dynamical mechanisms such as the axion, strongly motivating experimental searches for it. The lecture will be pedagogical and I will make these points using simple examples rather than complicated formalism.

Speaker: Surjeet Rajendran

14:30 Dark Matter at Colliders

The search for dark matter and dark sectors at colliders will be reviewed. Special attention will be paid to both heavy and light dark matter scenarios in which the dark matter is a thermal relic, but other possibilities that inspire interesting collider searches will also be included.

Speaker: Jonathan Lee Feng (University of California Irvine (US))

14:55 Dark Matter Production in Unusual Cosmologies

I will discuss how the assumption of a standard cosmological history can play a large role in the production of dark matter in the early Universe, and explore a few examples in which a nonstandard history can point to radically different parameters and/or models of dark matter to explain its observed abundance than one would have inferred from the standard assumptions about the conditions in the Universe at early times.

Speaker: Tim M.P. Tait (University of California, Irvine)

15:20 → 16:20 Coffee Break

16:20 → 18:00 SESSION 4: Direct Dark Matter Detection

16:20 Direct Detection with Xenon

NA

Speaker: Elena Aprile

16:45 Direct Detection with Argon

NA

Speaker: Cristiano Galbiati

17:10 Deep delving (and wide searching) with direct detection

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Speaker: Priscilla Cushman

17:35 The Status of Sub-GeV Direct Detection

NA

Speaker: Rouven Essig

Tuesday 25 March

07:30 → 08:00 Registration

08:00 → 09:45 SESSION 5: Astrophysics and Cosmology-1

08:00 Dark matter and neutrinos: from the early universe to near-field cosmology

Cosmological observables, from the Lyman-alpha forest to Milky Way substructure, offer unique avenues for testing new physics. I will review the status of the recent early-universe and late-universe searches for the identity of dark matter and for new physics in the neutrino sector, summarizing the best current limits on scattering between dark matter and baryons and neutrino self-scattering. I will highlight the interplay between complementary probes and discuss the prospects for unveiling the physics of dark matter in the coming decade.

Speaker: Vera Gluscevic (University of Southern California)

08:15 Black Holes as Dark Matter

The possibility that some of the black holes in the universe have a non-stellar origin and that they play a significant role in cosmology - including being some or all of the dark matter - is both timely and intriguing. I will review the status of the field, describe search strategies and future prospects for detection across many decades in mass, discuss how primordial black holes could seed both baryonic and particle dark matter in the very early universe, and argue that the search for sub-solar mass black holes may lead to a deeper understanding of the elusive Galactic "rogue planets".

Speaker: Stefano Profumo

08:30 Simulating dark matter subhalos

Many astrophysical probes of dark matter (strong lensing, perturbations to stellar streams, abundances and structure of dwarf galaxies) are sensitive to the number and properties of dark matter subhalos. Accurate inference from observations requires reliable and versatile models of subhalo populations. I will describe our latest generation of subhalo population models, which provide fast and accurate populations that can be used in forward modeling approaches. Key new features include support for a wide range of dark matter phenomenology (include SIDM, and decaying models), updated tidal evolution physics, and machine learning emulation for even faster model generation.

Speaker: Andrew Benson

08:45 Constraints on dark matter properties from the JWST lensed quasar dark matter survey

The JWST lensed quasar dark matter survey has delivered precise measurements of image flux ratios in 31 quadruply-imaged quasars. The compact emission surrounding the background AGN, which is now accessible with JWST, experiences significant perturbation from dark matter subhalos and field halos along the entire line of sight. As a result, this dataset is a powerful tool for characterizing the properties of dark matter substructure, and by extension, the particle nature of dark matter. I will present constraints on dark matter properties from an analysis of the full JWST sample, including the joint modeling of image flux ratios and the extended lensed arcs that encircle the main deflector. I will discuss implications for the particle nature of dark matter, and describe new ways this dataset can be utilized to explore the physics of dark sectors in the coming years.

Speaker: Daniel Gilman

09:00 COZMIC: Cosmological Zoom-in Simulations with Initial Conditions Beyond CDM

I will present COZMIC, a suite of over 100 cosmological zoom-in simulations with initial conditions beyond CDM. COZMIC spans initial conditions for warm, fuzzy, and interacting dark matter models. The shape of the linear matter power spectrum, P(k), is imprinted on the corresponding subhalo populations. Modeling this effect improves fuzzy and interacting dark matter bounds from the Milky Way satellite population by orders of magnitude. Simulations with a fractional non-CDM component also suppress subhalo abundances, yielding new limits on mixed cold/warm dark matter models. Finally, combining P(k) suppression with strong, velocity-dependent DM self-interactions alters core collapse, revealing an interplay between early and late-universe DM physics.

Speaker: Ethan Nadler (UC San Diego)

09:15 Extending MeV Dark Matter Bounds with COSI

Indirect dark matter detection in the MeV energy range is notably constrained by our limited observing sensitivity in this regime. The Compton Spectrometer and Imager (COSI), selected as a NASA Small Explorer satellite with an expected launch in 2027, will offer new potential to push these boundaries. COSI is a gamma-ray telescope that will survey the sky from 0.2-5 MeV with excellent energy resolution. The instrument comprises 16 cross-strip germanium detectors that provide imaging, polarimetry, and spectroscopy. Its instantaneous field of view is >25% of the sky with all-sky coverage every day. COSI’s primary science goals are to reveal galactic element formation, study extreme environments with polarization, detect gamma-ray bursts, and image the Galactic positron annihilation line. The same instrument features that enable COSI’s science goals – wide field of view, all-sky coverage, and exceptional energy resolution – make COSI excellent for exploring the MeV dark matter parameter space. COSI will search for spectral line signatures from the decay and annihilation of MeV scale dark matter candidates, potentially extending existing bounds by an order of magnitude or more. COSI also has the potential to explore continuum signals from primordial black hole evaporation and annihilation and decay of sub-GeV dark matter into leptons or photons. This talk will review the COSI mission, the instrument characteristics that make COSI excellent for dark matter searches, and the efforts being pursued to study COSI’s dark matter sensitivity. By extending our current observing capabilities in the 0.2-5 MeV energy range, COSI will enable the exploration of a previously-unprobed dark matter parameter space.

Speaker: Robin Ma'ila Anthony-Petersen

09:30 Status and Potential for Detection of Warm Dark Matter in Structure Formation and X-ray Astronomy

At dwarf galaxy scales and smaller, the thermal and kinetic properties of dark matter influence the growth of cosmological and galactic structures. These effects are observable through various methods, including dwarf galaxy counts, the Lyman-alpha forest, and strong lensing. I will review the current constraints and evidence for a small-scale cutoff in structure formation, consistent with warm dark matter (WDM). Additionally, I will examine the status of ongoing efforts to probe WDM particle decay using X-ray observatories and discuss the sensitivities of future missions. Sterile neutrino dark matter, a leading candidate for WDM, can be produced through various mechanisms in the early Universe, including enhanced production via non-standard interactions (NSI) among active neutrinos or via lepton-number driven resonant production via the Shi-Fuller mechanism. I will provide an overview of these production mechanisms, their interplay with structure formation constraints, and their implications for X-ray astronomy and neutrino NSI searches.

Speaker: Kevork Abazajian (University of California, Irvine)

09:45 → 10:15 Coffee Break

10:15 → 12:00 SESSION 6: Astrophysics and Cosmology-2

10:15 Status of cosmic antinuclei searches

The precise measurement of cosmic antinuclei is an important means for identifying the nature of dark matter and other beyond-standard-model physics. Recent years have shown that identifying the nature of dark matter with cosmic positrons and antiprotons is challenging and has led to an increased interest in cosmic antideuteron and antihelium searches. Antideuterons and antihelium nuclei may also be generated in dark matter annihilations or decays, offering a potential breakthrough in unexplored phase space for dark matter. This presentation discusses the current status, perspectives, and challenges for cosmic antinuclei searches. It will review the motivation for antinuclei searches, discuss the theoretical and experimental uncertainties of antinuclei production and propagation in our Galaxy, as well as summarize the experimental status.

Speaker: Philip Von Doetinchem (University of Hawaii at Manoa)

10:30 A Tale of Two Black Hole Populations

I will discuss our recent analysis of the LIGO GW catalogue that suggests two separate, unmixed, BH populations, potentially with different spatial distributions or origins. I will also discuss suggestive results from a recent analysis of microlensing towards the galactic bulge.

Speaker: Simeon Bird

10:45 Long-Range Dark Matter Self-Interactions in FIRE Simulations

In this talk, I present the first results from a new suite of Feedback in Realistic Environments (FIRE) simulations in which the dark matter is subject to a long-range self-interaction. This self-interaction takes the form of an attractive Yukawa potential parametrized by the strength of the force and its screening length, which we simulate on kiloparsec to megaparsec scales. We simulate galaxies on mass scales ranging from classical dwarfs to Milky Way-mass galaxies. The addition of a long-range dark matter self-interaction has dramatic effects on the formation of galaxies and their host halos: relative to $\Lambda$CDM, structure formation occurs at a higher redshift, and both central halos and subhalos can be more compact than their CDM counterparts. These features suggest that long-range dark matter self-interactions may alleviate several tensions in $\Lambda$CDM cosmology, such as the rotation curve diversity problem (in which some observed galaxy rotation curves are cuspier than rotation curves predicted by simulations with CDM). While past work has sought to constrain long-range dark matter self-interactions on cosmological scales, we present galaxy-scale constraints from comparisons between these simulations and observational data.

Speaker: Isabel Sands (Caltech)

11:00 Probing DM Substructure with Dynamical Heating in Ultra-Faint Dwarfs

NA

Speaker: Peter Graham (Stanford)

11:15 Mapping out Dark Matter in the Milky Way

In this talk, I will explore the interfacing of simulations, observations, and machine learning techniques to construct a detailed map of Dark Matter in the Milky Way, focusing on the Galactic Center/Halo and dwarf galaxies. For the Galactic Halo, I will present a recent work that reveals a decline in the stellar circular velocity, inducing tensions with established estimates of the Milky Way's mass and Dark Matter content. I will discuss how the underestimated systematic errors in such a common methodology necessitates a revised approach that combines theory, observations, and machine learning. In dwarf galaxies, I will present a novel Graph Neural Network methodology that facilitates the accurate extraction of Dark Matter density profiles, validated against realistic simulations. I will conclude with a discussion on the future trajectory of astroparticle physics, emphasizing the need for the integration of astrophysical probes with experimental Dark Matter research, potentially leading to a better understanding of the nature of Dark Matter.

Speaker: Lina Necib (MIT)

11:30 Primordial Black Holes as Dark Matter Candidates: O(α) Corrections to Hawking Radiation

Primordial black holes (PBHs) in the mass range $10^{17} - 10^{22} \, \text{g}$ are a promising candidate for the dark matter. At the lower end of this range, PBHs emit Hawking radiation with temperatures $T_H \gtrsim 100 \, \text{keV}$, allowing for electron-positron pair production and making their radiation detectable in high-energy surveys. To interpret these signals, it is crucial to account for O($\alpha$) corrections to the Hawking radiation spectrum.

This work focuses on the perturbative calculation of these O($\alpha$) corrections in a Schwarzschild geometry, starting with the quantization of photon and electron/positron fields. We compute the dissipative corrections, which arise from pair creation and annihilation in the plasma. Our numerical results for asteroid-mass PBHs (with masses $M = 1 - 8 \times 10^{21} \, m_{\text{Planck}}$) confirm that at low energies, bremsstrahlung radiation dominates the spectrum, while at high energies, pair production causes a slight suppression of the photon flux.

By comparing our results to existing approximation schemes, we find deviations that could impact the interpretation of Hawking radiation and the constraints on PBHs as dark matter candidates.

Speaker: Makana Silva (Los Alamos National Laboratory)

11:45 Limits on primordial black holes as dark matter from two decades of the OGLE survey

The idea that dark matter may be composed of dark compact objects, such as primordial black holes, was revived following the discoveries of gravitational waves from mergers of massive black holes by the LIGO and Virgo detectors.

If such black holes existed in large numbers in the Milky Way dark matter halo, they would cause long-timescale gravitational microlensing events lasting years. Previous experiments that aimed to detect gravitational microlensing events from dark matter halo objects were not sensitive to such long-timescale microlensing events and, thus, not sensitive to such massive black holes.

In this talk, I would like to present the results of the search for the long-timescale microlensing events amongst the light curves of nearly 80 million stars located in the Large Magellanic Cloud (LMC) that were monitored for 20 years (2001-2020) by the OGLE survey.

We did not find any events with timescales longer than 1 yr. The properties of all thirteen microlensing events with timescales shorter than 1 yr detected by OGLE toward the LMC can be explained by stars and brown dwarfs located either in the LMC itself or in the Milky Way disk, without the need to invoke dark matter in the form of compact objects.

We find that compact objects in the mass range from 1.4e-8 (half of the Moon mass) to ~10 solar masses cannot compose more than 1% of dark matter, and compact objects in the mass range from 3.5e-9 to 860 solar masses cannot make up more than 10% of dark matter. The weaker limits extend up to 10^4 solar masses.

Our limits are more than an order of magnitude stronger than those inferred by all previous gravitational microlensing experiments that aimed to assess the contribution of compact objects in the relevant mass range to dark matter.

Speaker: Przemek Mróz

12:00 → 13:00 Lunch Break

13:00 → 13:30 SESSION 7: Laboratory and Accelerator Based and Indirect Detection

13:00 Model Independent Searches for sub-MeV Particles with Rare Isotope Doped Superconducting Sensors

NA

Speaker: Kyle Leach

13:15 Antihelium from Dark Matter Annihilation

Observations by AMS-02 on the International Space Station have tentatively detected approximately 10 events that are consistent with antihelium nuclei. This observation is of significant interest due to the difficulty in producing any detectable antihelium flux through standard model interactions. In this talk, I will discuss the state of these observations, focusing on detailed theoretical models that may be able to significantly enhance the antihelium flux from dark matter annihilation, including: (1) a previously-missed standard model mechanism where $\overline{\Lambda_b}$ particles produced by dark matter can efficiently decay into antihelium nuclei, (2) the possibility that the dark sector includes dark-QCD interactions which can efficiently produce multi-baryon final states that efficiently coalesce into antihelium (and even more exotic) particles. I will discuss the possibility that rare decays into antihelium may beat the more popular gamma-ray, antiproton, and positron channels to produce the first evidence of particle dark matter.

Speaker: Tim Linden

13:30 → 14:15 SESSION 8: Dark Matter Theory

13:30 Cosmic Millicharge Background and Reheating Probes

We demonstrate that the searches for dark sector particles can provide probes of reheating scenarios, focusing on the cosmic millicharge background produced in the early universe. We discuss two types of millicharge particles (mCPs): either with, or without, an accompanying dark photon. These two types of mCPs have distinct theoretical motivations and cosmological signatures. We discuss constraints from the overproduction and mCP-baryon interactions of the mCP without an accompanying dark photon, with different reheating temperatures. We also consider the ΔNeff constraints on the mCPs from kinetic mixing, varying the reheating temperature. The regions of interest in which the accelerator and other experiments can probe the reheating scenarios are identified in this paper for both scenarios. These probes can potentially allow us to set an upper bound on the reheating temperature down to ∼10 MeV, much lower than the previously considered upper bound from inflationary cosmology at around ∼10^{16} GeV. In addition, we find parameter regions in which the two mCP scenarios may be differentiated by cosmological considerations. Finally, we discuss the implications of dedicated mCP searches and future CMB-S4 observations.

Speaker: Yu-Dai Tsai (University of California, Irvine)

13:45 Axions and the formation of supermassive black holes at cosmic dawn

Axion dark matter thermalizes by gravitational self-interactions and forms a Bose-Einstein condensate. It is shown that the rethermalization of the axion fluid during the initial collapse of large scale overdensities at cosmic dawn transports angular momentum outward sufficiently fast that black holes form with masses ranging from approximately $10^5$ to a few times $10^{10}~M_\odot$.

Speaker: Pierre Sikivie

14:00 → 16:00 SESSION 8: Dark Matter Theory

14:00 Dark matter halos at z > 6 through gas kinematics

NA

Speaker: John Silverman

14:45 Macroscopic dark matter: fermi balls and black holes

I will discuss the formation of macroscopic dark matter from interacting dark sectors. Specifically,Fermi balls can form in dark sectors with a heavy fermion and a light scalar mediated Yukawa force. I'll discuss the behavior of these Fermi balls and the conditions under which they will collapse to form primordial black holes. Based on arXiv:2411.17074.

Speaker: zachary picker (UCLA)

15:00 Gravitational Waves from Black Hole formation

In an early matter phase of the Universe, perturbations can
grow and lead to the formation of primordial black holes that can account
fully or partially for the observed dark matter abundance. During
formation, such primordial black holes can produce gravitational waves
that can be detected in interferometers or in Pulsar Timing Arrays. I'll
present results from numerical simulations that depict the nonlinear
perturbation growth and formation of the primordial black holes as well
as the subsequent gravitational wave production.

Speaker: Chris Kouvaris

15:30 Probing Gravothermal Collapse of Dark Matter Halos: Observational Insights

I will discuss the probing of gravothermal collapse of dark matter halos through stellar streams and strong lensing systems.

Speaker: Hai-Bo Yu (University of California Riverside)

15:45 Q-balls with an Attractive Force

We consider the Friedberg-Lee-Sirlin Q-ball with a renormalizable cubic interaction. This attractive Yukawa interaction balances the quartic interaction and results in more compact Q-balls with a maximum stable charge. We show that our numerical simulations match our analytic calculations of the maximum charge. Additionally, we consider the fate of these unstable Q-balls with excess charge, and their possible implications for cosmology.

Speaker: Philip Lu (KIAS)

14:15 → 14:45 Coffee Break

16:00 → 18:00 SESSION 9: Poster Session #1

18:00 → 20:00 Conference Banquet

Wednesday 26 March

07:30 → 08:00 Registration

08:00 → 10:00 SESSION 10: Direct Detection: status of liquid/gas WIMP detectors

08:00 Dark matter direct detection with PandaX experiment

Located at the China Jinping Underground Laboratory, the PandaX experiment employs xenon as a target to detect rare physics signals, such as dark matter and neutrinos. The PandaX-4T, the latest generation detector featuring a 4-ton xenon target volume, commenced data collection in 2020. One of our objectives is to unravel the nature of dark matter by investigating various potential signatures. In this talk, I will present the most recent results of the dark matter search using the PandaX-4T physics run data, and also give a brief overview of the future prospects of the PandaX experiment.

Speaker: Prof. Ning Zhou (Shanghai Jiao Tong University (CN))

08:15 Dark Matter Search Status from DEAP-3600

The current status of the search for dark matter from the DEAP-3600 experiment will be presented, along with a detailed description of the analysis techniques. DEAP-3600 is a direct detection experiment that uses 3.3 tonnes of liquid argon as its target material. Located over 2 km underground at SNOLAB in Sudbury, Canada, the detector is designed to observe scintillation light from nuclear recoils induced by dark matter interactions. Pulse-shape discrimination is employed to suppress the dominant background from beta decays of argon-39. Additional backgrounds include alpha decays from the inner surface of the detector and from dust within the liquid argon, radiogenic neutrons from detector components, and Cherenkov radiation.

Speaker: Spencer Haskins

08:30 The PICO-40L Direct Detection Experiment

To continue to make progress in the global effort to understand the nature of dark matter, it is essential to further explore the spin-dependent WIMP-nucleon interaction parameter space. The PICO-40L bubble chamber is a dark matter direct detection experiment located at the SNOLAB underground research facility outside Sudbury, Canada. The abundance of non-zero-spin fluorine nucleons in the superheated C3F8 target fluid gives PICO-40L the potential to set world-leading exclusion limits for WIMP-proton interactions. PICO-40L is fully assembled and currently in the commissioning phase. An overview of the detector and analysis strategy, as well as the results from some early commissioning runs, will be presented in this talk.

Speaker: Derek Cranshaw

08:45 Status of the LUX-ZEPLIN Dark Matter Experiment

LUX-ZEPLIN (LZ) is a direct detection dark matter experiment located nearly a mile underground at the Sanford Underground Research Facility in South Dakota, USA employing a 7 tonne active volume of liquid xenon in a dual-phase time projection chamber (TPC). It is further surrounded by a three-component veto system: an instrumented 2-tonne liquid xenon skin, a near-hermetic gadolinium-loaded liquid scintillator, and instrumented, ultra-pure water tank. The experiment has been taking data since 2021, and in 2024 released world-leading constraints excluding WIMP-nucleon cross-sections to WIMP masses $\geq$ 9 GeV/c$^{2}$. This talk will discuss the status of the LZ experiment and report on its recent science results.

Speaker: Daniel Kodroff

09:00 DarkSide-20k Physics Potential for Dark Matter direct searches

The DarkSide program at Laboratori Nazionali del Gran Sasso (LNGS) aims to detect dark matter WIMP particles using a dual-phase Liquid Argon (LAr) Time Projection Chamber (TPC). Since 2015, the DarkSide-50 detector, featuring a 50-kg active mass dual-phase LAr TPC filled with low-radioactivity argon sourced from underground, has produced world-class results for both low-mass and high-mass direct detection searches. The next stage of the DarkSide program will be a new generation experiment involving a global collaboration from all the current Argon based experiments.
The upcoming DarkSide-20k experiment is designed to exploit a 20-tons fiducial mass dual-phase LAr TPC equipped with SiPM-based cryogenic photosensors. Like its predecessor, DarkSide-20k will be hosted at the INFN LNGS underground laboratory. It is expected to reach a WIMP-nucleon cross-section exclusion sensitivity of $7.4\times 10^{-48}\, cm^2$ for a WIMP mass of $1 TeV/c^2$ in a 200 t yr exposure.
This presentation will provide an overview of the recent DarkSide-50 results and the projected physics capabilities of DarkSide-20k, focusing on both the WIMP framework and the light dark matter searches.

Speaker: Alessio Caminata

09:15 Latest results on the search for WIMPs with XENONnT

The primary goal of the XENONnT experiment is to search for weakly interacting massive particles (WIMPs), a leading theoretical candidate for dark matter. In its second science run, XENONnT accumulated a total live time of ~186 days. During this run, the radon removal system was operated in high-flow mode, achieving a significant reduction of about 50% in the concentration of Rn-222 compared to the first science run. In this talk, I will present the XENONnT's latest results from a blind analysis to search for WIMPs with a mass above 10 GeV/$c^2$ combining both first and second science runs for a total live time of ~283 days.

Speaker: Zihao Xu

09:30 Enhanced recombination of $^{124}$Xe and the flow-tag of $^{214}$Pb in LUX-ZEPLIN

In this talk I will describe analyses of two of the most notable backgrounds in the recent LUX-ZEPLIN (LZ) dark matter search: $^{124}$Xe double L-shell capture decays and $^{214}$Pb daughters of $^{222}$Rn. First, we observe that $^{124}$Xe double L-shell capture decays have charge yields deviating 30% from standard electronic recoil (ER) backgrounds, resulting in increased overlap with high-mass WIMPs. This effect was expected from the measured charge yields of related decays, indicating that enhanced electron-ion recombination arising from larger ionization densities is responsible. Next, the largest background in the WIMP search comes from $^{214}$Pb decays following $^{222}$Rn emanation into the liquid. To mitigate these events, we have developed methods to control and map the flow of the liquid xenon in LZ. The flow maps are used to derive temporally-evolving volumes – representing 15% of the recent WIMP search exposure – that contain around 60% of $^{214}$Pb beta decays. Finally, I will describe how the flow-tag and enhanced recombination are relevant to calibrations, sidebands, and future dark matter searches.

Speaker: Chami Amarasinghe

09:45 Enhancing Direct Detection of Higgsino Dark Matter

While much supersymmetric WIMP parameter space has been ruled out, one remaining important candidate is Higgsino dark matter. The Higgsino can naturally realize the "inelastic dark matter" scenario, where the scattering off a nucleus occurs between two nearly-degenerate states, making it invisible to WIMP direct detection experiments if the splitting is too large to be excited. It was realized that a "luminous dark matter" detection process, where the Higgsino upscatters in the Earth and subsequently decays into a photon in a large neutrino detector, offers the best sensitivity to such a scenario. We consider the possibility of adding a large volume of a heavy element, such as Pb or U, around the detector. We also consider the presence of U and Th in the Earth itself, and the effect of an enhanced high-velocity tail of the dark matter distribution due to the presence of the Large Magellanic Cloud. These effects can significantly improve the sensitivity of detectors such as JUNO, SNO+, and Borexino, potentially making it possible in the future to cover much of the remaining parameter space for this classic SUSY WIMP dark matter.

Speaker: Mr Samuel Wong (Stanford University)

10:00 → 10:30 Coffee Break

10:30 → 12:30 SESSION 11: Direct Detection: status of crystalline WIMP detectors

10:30 The SuperCDMS experiment at SNOLAB

The Super Cryogenic Dark Matter Search (SuperCDMS) experiment, currently being installed 2 km underground at SNOLAB Canada, is a collaborative effort to search for low-mass dark matter particles (<10 GeV/c²) via direct detection. The experiment utilizes 24 silicon and germanium crystals instrumented with either phonon sensors, called HV detectors, or, phonon and charge sensors, called iZIP detectors. These detectors will be stacked in 4 towers, with each tower containing 6 detectors. The HV detectors operate at high voltage (~100 V), leveraging the Neganov-Trofimov-Luke effect to amplify phonon signals and achieve a lower energy threshold. The iZIP detectors provide precise discrimination between electronic and nuclear recoils, substantially reducing the background. The combination of these technologies positions SuperCDMS uniquely to explore low-mass, low cross-section dark matter particles.

Installation is set to conclude by mid-2025 and will be followed by the commissioning phase. The first science run is anticipated to begin by late 2025. Additionally, the collaboration recently tested one HV detector tower between October 2023 and February 2024 in the Cryogenic Underground TEst facility (CUTE), located adjacent to the main experimental area at SNOLAB. This talk will provide an overview of the SuperCDMS experiment, its current progress, and key results from the CUTE tower testing.

Speaker: Shubham Pandey (University of Minnesota, Twin Cities)

10:45 The SABRE North experiment at LNGS to search for Dark Matter annual modulation

The SABRE experiment aims to deploy arrays of ultra-low-background NaI(Tl) crystals to carry out a model-independent search for dark matter through the annual modulation signature. SABRE will be a double-site experiment, consisting of two separate detectors in the two terrestrial hemispheres, reliant on a joint crystal R&D activity. The SABRE North detector will be installed underground at LNGS and will deploy ultra-high radio-purity NaI(Tl) detectors in a Cu and PE passive shielding. The expected background rate in the ROI [1,6] keV is of order 0.5 dru. To this end SABRE North will make use of zone refining purification of the NaI powder. The collaboration has recently confirmed the technology to produce 5 kg size NaI(Tl) crystals after zone refining purification of the powder. This is a breakthrough in the production of ultra-high radio-purity NaI(Tl) scintillators. Based on this development SABRE North is starting crystal production. The first crystal after zone refining will be delivered at LNGS in early 2025 for characterization. The SABRE North detector will be equipped with 9 crystals of about 5 kg each located inside a thin Cu box and shielded against environmental background with Cu and PE.
Results from zone refining runs and crystal growth development will be reported together with the potential of the detector for the specific physics case. Segregation coefficients of different impurities will be reported to show how this method is more or less effective to reduce background components which limit the dark matter search sensitivity. The time schedule of crystal production and detector deployment will be reported.

Speaker: Aldo Ianni (INFN LNGS)

11:00 Towards a robust model-independent test of DAMA/LIBRA: ANAIS-112 six-year exposure results and prospects

The ANAIS experiment aims to verify or refute in a model independent way with a high statistical significance the longstanding positive annual modulation signal observed by DAMA/LIBRA. For this goal, ANAIS experiment uses the same target, NaI(Tl), and technique, the analysis of the annual modulation in the scintillation signal observed at very low energy. ANAIS−112 consists of nine modules, 12.5 kg each, of NaI(Tl) arranged in a 3×3 configuration, plus a blank module without NaI(Tl) crystal. ANAIS-112 has been continuously collecting data at the Canfranc Underground Laboratory in Spain since August 2017, demonstrating outstanding performance. Updated results with six-year exposure will be presented: they are consistent with the absence of modulation and incompatible with the DAMA/LIBRA result with a sensitivity above 4σ C.L. Systematics affecting this test will be analysed and discussed. Finally, updated sensitivity projections will be provided, pointing at a 5σ exclusion of the DAMA/LIBRA signal with the data accumulated by the end of 2025.

Speaker: María Luisa Sarsa (University of Zaragoza)

11:15 Status of CRESST

CRESST-III (Cryogenic Rare Event Search with Superconducting Thermometers) installed at Laboratori Nazionali del Gran Sasso, is looking to directly detect dark matter particles scattering off CaWO4 target nuclei in cryogenic detectors. Thanks to its energy threshold O(30 eV), CRESST-III is particularly suitable in probing sub-GeV DM masses. This contribution presents an overview of CRESST-III, reporting the latest DM results and plans for the future. Recent achievements are discussed on the Low Energy Excess (LEE), an unexplained rise of events at low energies (<200 eV). The most recent experimental campaign, using the Double TES approach to identify the origin of LEE and reject this background, is also discussed.

Speaker: Josef Jochum (Universitaet Tuebingen)

11:30 Overview of the SuperCDMS-HVeV Program

The SuperCDMS-HVeV (High-Voltage with eV resolution) program is an
R&D project focused on developing detectors with high energy resolution to search for low-mass dark matter (≲ 1 GeV/c2), study charge-transport in cryogenically-cooled crystals, and probe unclassified backgrounds at low energy. The program utilizes gram-scale silicon detectors instrumented with TES (transition-edge sensor)-based phonon sensors. A high-voltage bias can be applied to the crystal to amplify phonon signals from ionizing interactions via the Neganov-Trofimov-Luke effect. In 2022, a dark matter search was conducted using HVeV detectors near surface (225 w.m.e. overburden) at Northwestern’s EXperimental Underground Site (NEXUS) at Fermilab in Batavia, IL which demonstrated competitive sensitivities to dark matter at masses ≲ 1 MeV/c2 and sub-single-electron-hole pair thresholds. Since then, a detector using a modified HVeV design has been operated at the Cryogenic Underground TEst (CUTE) facility at SNOLAB (Sudbury, ON) to classify and mitigate backgrounds which are the main limitation to sensitivity across the community of experiments searching for low-mass dark matter.
This talk will provide an overview of the SuperCDMS HVeV program, results of the dark matter search at Fermilab, and key findings in the background studies at CUTE which further improve sensitivity to low-mass dark matter.

Speaker: Kyle Kennard

11:45 COSINUS - towards the clarification of the puzzling DAMA/LIBRA signal

A method for distinguishing dark matter signals from detector background is looking for an annual modulation signal caused by the seasonal variation of the Earth’s velocity with respect to the sun and, thus, the dark matter halo.
The DAMA/LIBRA experiment, a pioneer using such modulation as DM signature, observes a modulated signal rate with a very high statistical significance with the period and phase matching the DM expectation.
The DAMA/LIBRA results are in strong tension with the null results of most of the other direct dark matter searches. However, as of today, a material and model-independent unambiguous cross-check is still missing to unveil this long-term puzzle.
COSINUS, one of several NaI experiments, is working towards this goal by employing sodium iodide as a low-temperature scintillating calorimeter.
The distinctive features of COSINUS, compared to the other NaI searches, are a low threshold for nuclear recoils, superior energy resolution, and particle identification on an event-by-event basis.
In this talk, I will discuss the latest results from the COSINUS prototype detector, the status of the novel cryogenic low-background facility located at the Gran Sasso underground lab, and the last steps of the commissioning towards starting the first physics data-taking campaign in 2025.

Speaker: Karoline Julia Schaeffner (Max-Planck Institute for Physics)

12:00 Novel substrates and readout systems for crystal-based direct dark matter detection

Crystal-based detectors like those of SuperCDMS SNOLAB provide the most sensitive searches for a variety of dark matter candidates. Low-noise environments and transition-edge sensors (TES) for phonon detection have enabled the measurement of interaction energies with eV-scale resolution over a large dynamic range. As we approach the fundamental limitations of these detectors, however, there is growing interest in the use of alternative detector substrates, such as diamond and silicon carbide (SiC). Different substrate materials have sensitivity to differing interaction energies and can support higher voltages with lower dark count rates, among other advantages. We report on the performance of the first TES-based SiC detectors, fabricated at Stanford. We also discuss our SQUID-based readout system, recently used at SNOLAB, as well as other technologies being explored, including single-electron readout devices, KIPMs, and SQUATs.

Speaker: James Ryan

12:15 The SABRE South Experiment at the Stawell Underground Physics Laboratory

SABRE is an international collaboration that will operate similar particle detectors in the Northern (SABRE North) and Southern Hemispheres (SABRE South). This innovative approach distinguishes possible dark matter signals from seasonal backgrounds, a pioneering strategy only possible with a southern hemisphere experiment. SABRE South is located at the Stawell Underground Physics Laboratory (SUPL), in regional Victoria, Australia.
SUPL is a newly built facility located 1024 m underground (∼2900 m water
equivalent) within the Stawell Gold Mine and its construction has been completed in 2023.
SABRE South employs ultra-high purity NaI(Tl) crystals immersed in a Linear Alkyl Benzene (LAB) based liquid scintillator veto, enveloped by passive steel and polyethylene shielding alongside a plastic scintillator muon veto. Significant progress has been made in the procurement, testing, and preparation of equipment for installation of SABRE South. The SABRE South muon detector and the data acquisition systems are actively collecting data at SUPL and the SABRE South’s commissioning is planned to be completed by the end of 2025.
This presentation will provide an update on the overall progress of the SABRE South construction, its anticipated performance, and its potential physics reach.

Speaker: Phillip Urquijo (The University of Melbourne)

12:30 → 13:30 Lunch Break

13:30 → 15:30 SESSION 12: Direct Detection: status of Light DM detection

13:30 The search for light dark matter with DAMIC-M

The DAMIC-M (DArk Matter In CCDs at Modane) experiment will use skipper CCDs to search for low mass (sub-GeV) dark matter underground at the Laboratoire Souterrain de Modane (LSM). With about 1kg of silicon target mass and sub-electron energy resolution, the detector will surpass the exposure and threshold (eV-scale) of previous experiments. As such, DAMIC-M will have world-leading sensitivity to a variety of “hidden sector” dark matter candidates. In this talk, we will report on science results from a prototype detector, test performance of CCD modules, and the status of the detector construction at LSM.

Speaker: Danielle Norcini (Johns Hopkins University)

13:45 Latest results and prospects of the SENSEI experiment.

SENSEI (Sub-Electron Noise Skipper Experimental Instrument) is the first experiment to implement silicon skipper CCDs to search for dark matter. Skipper-CCDs can resolve single electrons in each of millions of pixels, which allows for the low energy threshold required to detect sub-GeV dark matter interacting with electrons. SENSEI recently measured the lowest event rates containing one electron in silicon detectors, resulting in world-leading sensitivity. In this talk, we present the latest results from two science runs at SNOLAB as well as the future prospects for SENSEI.

Speakers: Ana Martina Botti (Fermilab), SENSEI Collaboration

14:00 The DarkSide-LowMass search for dark matter below 10 GeV/c^2

DarkSide-LowMass is a tonne-scale liquid argon time projection chamber (LArTPC) being planned by the Global Argon Dark Matter Collaboration (GADMC) to search for WIMP-like dark matter with masses below 10 GeV/c^2, achieving low thresholds with a design optimized for an electron-counting analysis. Building upon the success of DarkSide-50's light dark matter search, DarkSide-LowMass will aim to achieve sensitivity to the solar neutrino floor with a tonne-year exposure. This talk will present sensitivity projections for the DarkSide-LowMass experiment, based on simulations of expected backgrounds, and it will discuss challenges to optimizing sensitivity.

Speaker: Shawn Scott Westerdale (University of California Riverside (US))

14:15 Search for electronic recoil signals with XENONnT

The XENONnT experiment searches for weakly interacting massive particles scattering off xenon nuclei with a dual-phase time projection chamber. With 5.9 tonnes of active mass and an unprecedented low level of background, the detector enables the searches of several rare-event physics channels. In particular XENONnT set stringent limits on other dark matter candidates interacting through electronic recoil (ER) scatter, such as solar axions and bosonic dark matter. The excellent energy reconstruction up to the MeV scale allows to conduct analysis also on other processes producing ER signals, like double-weak decays of Xe124 and Xe136 or precision measurements on nuclear transition such as the branching ratio of Pb212 and the spectral shape of Bi214. In this talk I will give an overview of the results and the ongoing studies on electronic recoil signals with XENONnT.

Speaker: Chiara Capelli (University of Zurich)

14:30 The TESSERACT Project

TESSERACT is currently in an R&D and planning phase, funded under the DOE Dark Matter New Initiatives program. This phase will result in two fully defined experiments (HeRALD and SPICE). Collaboration with French groups has recently been formalized, bringing a third technology to the suite. We will provide an overview of this general TESSERACT program as we transition to `project’ phase. In parallel to the ongoing effort of detector testing and demonstration, planning is accelerating for a facility of shielded dilution refrigerators at Modane Underground Laboratory. I will end by discussing the projected sensitivities of this ambitious and diverse TESSERACT detector suite to a wide range of sub-GeV dark matter masses and interaction types.

Speaker: Prof. Scott Hertel (U. Massachusetts, Amherst)

14:45 Exploring New Physics with PandaX-4T Low Energy Electronic Recoil Data

PandaX-4T is a dual-phase liquid xenon (LXe) time projection chamber (TPC) detector that operates in China Jinping Underground Laboratories (CJPL). Searches for novel electronic recoil signals (NERS) from solar axions, axion-like particles (ALPs), dark photons, neutrinos with an enhanced magnetic moment and absorption of fermionic dark matter have attracted increasing attention in PandaX-4T and similar experiments. The observation of NERS could provide evidence of beyond-the-Standard-Model physics and the Majorana nature of neutrinos. We searched NERS with both run-0 and run-1 low-energy electronic recoil data of PandaX-4T.

Speaker: Xinning Zeng

15:00 Searching for dark sectors and X17 with PADME

PADME is a fixed-target, missing-mass experiment originally designed to search for dark photons using a beam of positrons with energy up to 500 MeV. The detector, located at the Laboratori Nazionali di Frascati, in Italy, has already collected initial physics data over the last few years. More recently, the experiment has been adapted to perform a direct search for on-shell X17 production. PADME will be able to provide independent confirmation of the anomalies observed in the ATOMKI spectroscopic measurements with Beryllium, Helium, and Carbon atoms. The new experimental setup and the prospects for the observation of X17 production will be discussed, and new upgrades to the detector that will greatly expand the physics program of PADME will be introduced.

Speaker: Andre Frankenthal (Princeton University (US))

15:15 A search for cosmic ray boosted light dark matter with the LUX-ZEPLIN experiment

Cosmic rays in the Milky Way may collide with sub-GeV dark matter, imparting sufficient kinetic energies to produce detectable signals in liquid xenon
detectors. In this talk, I will present a new analysis on light dark matter accelerated by cosmic rays (CRDM) in the Milky Way, using data from the LUXZEPLIN (LZ) experiment, a dual-phase xenon detector located at the Sanford
Underground Research Facility in Lead, South Dakota, USA. This analysis uses
a total exposure of 4.2 tonne-years from two science runs, and features a novel
technique for tagging background events from Pb-214 decays. Several important factors have been introduced and examined, including the contributions of
heavier cosmic ray nuclei beyond protons and helium, as well as the non-uniform
distribution of cosmic rays and dark matter within the Milky Way. Darkprop,
a Monte Carlo simulation package, was utilized to account for Earth’s shielding
effects, incorporating the chemical composition and the nuclear form factors of
atoms in the Earth’s crust for CRDM propagation. Our preliminary results,
which establish the most stringent constraints on the spin-independent dark
matter–nucleon scattering cross section for CRDM models with masses between
100 keV and 1 GeV will be presented.

Speaker: Yongheng Xu

15:30 → 16:00 Coffee Break

16:00 → 18:00 SESSION 13: Direct detection: Technical Development-1

16:00 The DarkSide-20k Experiment and the Search for Dark Matter with Underground Argon

The DarkSide-20k experiment represents the latest phase of the Global Argon Dark Matter Collaboration, leveraging expertise from previous argon-based detectors. This effort is focused on constructing a dual-phase liquid argon time projection chamber (LAr-TPC) that will deploy 100 tonnes of underground argon outfitted with silicon photomultiplier (SiPM) arrays for precise light detection. Currently in the construction phase, the external cryostat is being installed at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. This presentation will provide an overview of the DarkSide detector, hightlight its key design elements and its objectives, as well as updates on the ongoing construction of the underground infrastructure at LNGS.

Speaker: Dr Ako Jamil (Princeton University)

16:15 Hardware upgrades to the DEAP-3600 dark matter detector to enhance WIMP sensitivity

This talk describes hardware upgrades for the DEAP-3600 dark matter direct detection experiments, which uses over 3 tonnes of liquid argon (LAr) as a scintillation target and is located 2 km underground at SNOLAB in Sudbury, Canada. These upgrades aim to maximize the detector's sensitivity to WIMP dark matter by removing the dominant sources of background. Operations with the upgraded detector are expected to begin in 2025. The experiment holds the most stringent exclusion limit in argon for WIMP masses above 20 GeV/$c^2$, thanks to an extraordinary discrimination power between electronic and nuclear recoil pulses.
Sensitivity was limited by backgrounds induced by alpha activity. Over the years, the collaboration developed a thorough understanding of the backgrounds in DEAP-3600, in particular two leading alpha-particle backgrounds. The first category of events originates from the lower part of the detector neck, a shadowed region of the detector where only a fraction of scintillation light from LAr enters the central volume. An innovative pyrene-doped polystyrene wavelength-shifting coating was applied to the neck, allowing the tag of alpha neck events with a distinctly slow re-emission time constant compared to the TPB used elsewhere. The second category of events comes from degraded alphas from particulates in the LAr. A particulate filtration system and an upgrade of the LAr process systems allow for removal of any such particulates in the new LAr fill. These hardware upgrades will allow DEAP-3600 to significantly reduce the observed background, reach the designed WIMP sensitivity and test the feasibility of large-scale single-phase LAr detectors to achieve background-free conditions.

Speaker: Theo Hugues (Queen's University)

16:30 Progress and Results from the TESSERACT Dark Matter Experiment

The TESSERACT collaboration will search for dark matter particles below the proton mass through interactions with two types of novel, ultra-sensitive detectors. These detectors, SPICE and HeRALD, aim to provide leading sensitivities to low-mass dark matter candidates. In this talk I will present on the recent progress made toward reaching this goal. First, I will discuss the recent deployment of the HeRALD v0.2 detector at LBNL, as well as analysis highlights from the multi-channel upgrade of the HeRALD v0.1 detector at UMass. Then, I will showcase the achievements SPICE has made towards making world-leading energy resolution TESs. I will detail new insights on the “low energy excess” background and parasitic power relevant to cryogenic detectors. I will finish by highlighting results of TESSERACT’s first above-ground dark matter search, which yielded world-leading sensitivity to dark matter below 100 MeV/c^2.

Speaker: Michael Williams (Lawrence Berkeley National Laboratory)

16:45 The Scintillating Bubble Chamber

The Scintillating Bubble Chamber (SBC) collaboration is developing novel particle detectors sensitive to low-energy (sub-keV) nuclear recoils by combining existing bubble chamber technology with liquid noble detectors. This approach leverages the insensitivity to electronic recoils characteristic of bubble chambers alongside the scintillation yield from a liquid noble active medium. SBC aims to achieve lower detection thresholds through a multi-channel readout including acoustic, imaging, and scintillation signals. The collaboration is currently commissioning two identical 10-kg detectors: SBC-LAr10 and SBC-SNOLAB. SBC-LAr10, located at Fermilab will focus on detector calibration and CEvNS studies, while SBC-SNOLAB will be purpose-built for dark matter searches in the low-background environment at SNOLAB. This talk will provide an overview of scintillating liquid noble liquid bubble chambers and the current status of both detectors.

Speaker: Kenneth Clark

17:00 The XLZD Experiment

The XLZD Collaboration is developing an international experiment to search for WIMP dark matter down to the systematic limit imposed by astrophysical neutrinos. The experiment will be based on the heritage detector designs now operating at the 10-tonne scale implemented by the XENONnT and LUX-ZEPLIN collaborations, and further informed by work being carried out by the DARWIN R&D collaboration. These teams have used liquid xenon time projection chambers to probe WIMP parameter space to unprecedented levels. Building on these successes, we envision a new detector composed of at least 60-tonnes of active xenon surrounded by an outer detector to monitor and measure gamma and neutron backgrounds. XLZD will reach at least 200 tonne-years of exposure, and potentially up to 1000 tonne-years, allowing us to definitively explore the remaining WIMP parameter space. At this scale, XLZD will be able to competitively probe neutrinoless double-beta decay in xenon-136 and search for a broad range of new astrophysical neutrino phenomena.

Speaker: Prof. Daniel Akerib (SLAC)

17:15 Xenon-Doped Argon for Dark Matter Search

We will discuss the potential benefits of xenon doping in liquid argon for dark matter search experiments. Notably, doping liquid argon with xenon at the percent level is predicted to enhance the production and collection of electroluminescence light in a dual-phase argon detector, as well as improve its spatial resolution and temporal stability. At LLNL, we have constructed a test stand capable of doping liquid argon with over 5% xenon (by mole fraction) and have investigated the effects of xenon doping on the properties of electroluminescence signals. The potential of such a system for dark matter search will be presented.

Speaker: Dr Jingke Xu (Lawrence Livermore National Laboratory, USA)

17:30 Progress of the PICO-500 Detector installation

The bubble chamber approach of looking for spin dependent interactions between fluorine and dark matter has been quite impactful so far. The PICO collaboration is in the process of deploying PICO-500, a large 250 litre chamber filled with C₃F₈ at SNOLAB with an scheduled start of commissioning in late 2026. We will report on the design progress and the production aspects of the quality control and installation status of this new chamber at SNOLAB.

Speaker: Carsten Krauss (University of Alberta)

17:45 The International Axion Observatory (IAXO) and BabyIAXO (*)

The International Axion Observatory (IAXO) is a next-generation axion helioscope aiming at a sensitivity to the axion-photon coupling down to ~$1.5 \times 10^{-12}$ GeV$^{-1}$, approximately 1.5 orders of magnitude beyond current helioscopes, across a wide mass range up to ~0.25 eV. IAXO will probe QCD axions in the 1 meV∼1 eV mass range, where they could constitute all or part of the dark matter in the Universe, as well as a large part of parameter space that includes ALP dark matter candidates and other novel excitations at the low-energy frontier of particle physics. The collaboration is currently constructing BabyIAXO, as a preliminary step towards a full IAXO experiment. BabyIAXO will not only serve as a testbed for prototype magnet, X-ray optic, and detector systems, but also probe four times lower in axion-photon coupling than the current leading helioscope limits. In this contribution, we discuss the status of BabyIAXO and IAXO, as well as the anticipated science impact of each.

Speaker: Kerstin Perez

18:00 → 19:00 SESSION 14: Poster session #2

Thursday 27 March

07:30 → 08:00 Registration

08:00 → 09:45 SESSION 15: Direct detection: Technical Development-2 & Scientific Development

08:00 The Search for the Migdal Effect and the Modeling of Nuclear Recoil with DD Neutrons in LUX-ZEPLIN (LZ) Experiment

WIMP dark matter particles are expected to interact with liquid xenon producing nuclear recoils (NRs). It is critical for dark matter experiments to have accurate calibration of the detector response and correct modeling of xenon microphysics. The Migdal effect theorizes that when an atom is recoiling, an electron could be emitted, leading to ionization and greater energy deposition. This effect is crucial for dark matter experiments as it improves the sensitivity to sub-GeV dark matter. In this talk, we report the direct measurement of the rate of Migdal-effect events in liquid Xe for NR in the energy range of 5–74 keVnr, resulting from interactions of 2.45 MeV DD neutrons with xenon nuclei. We also present the NR yield calibration for the first science run of the LUX-ZEPLIN (LZ) experiment. The analysis of high-statistics data motivates significant revision of the model for xenon microphysics. We will discuss the impact of such revision on the search for the coherent scattering of boron-8 neutrinos.

Speaker: Mr Chen Ding (Brown University)

08:15 DarkNESS: probing dark matter from Low Earth Orbit with skipper-CCDs

The DarkNESS (Dark Matter Nano-satellite Equipped with Skipper Sensors) mission will deploy a skipper-CCD CubeSat Observatory to search for dark matter (DM) from Low Earth Orbit. During its time in orbit, DarkNESS will observe the Galactic Center to probe O(keV) X-rays from decaying DM models, as well as perform a direct search for electron recoils from strongly-interacting sub-GeV DM. The DarkNESS mission will be the first space deployment of skipper-CCDs, with a launch opportunity anticipated in late 2025. In this contribution, we describe the DarkNESS mission, focusing on its scientific objectives and recent programmatic milestones.

Speaker: Dr Nathan Saffold (Fermilab)

08:30 CrystaLiZe: Dark Matter Detection and Beyond with Crystal Xenon

We present the crystalline xenon time projection chamber (TPC), a promising novel technology for next-generation dark matter searches. Initial tests have established that it maintains many of the benefits of the liquid xenon TPC while also effectively excluding radon, the dominant background in currently-running xenon dark matter experiments such as LZ. This offers the potential for greatly improved sensitivity to dark matter through a crystal xenon upgrade to an existing experiment. This talk will discuss signal detection properties, radon exclusion performance, and progress towards a multi-kg demonstrator designed to establish its scalability.

Speaker: Scott Kravitz

08:45 Leveraging Quantum Sensors for Dark Matter Detection

Recent measurements have demonstrated that superconducting qubit decoherence is affected by radiation. As a result, many groups around the world are working to better understand the relationship between different types of radiation and qubit response. This crucial to quantum error correction because radiation can cause correlated loss of information across multiple qubits on a chip, defeating error correction algorithms. Additionally, the fundamental energy scale at which superconducting qubits operate may enable their development as meV-scale detectors for HEP applications, such as the direct detection of dark matter. At Fermilab, we have two world-class underground facilities which are already being used to study this problem: NEXUS and QUIET. I will present on results from operating superconducting qubits in each of these facilities, and the potential implications towards utilizing qubits as sensors for a novel dark matter detector.

Speaker: Daniel Baxter (Fermi National Accelerator Laboratory, USA)

09:00 The new Cryolab at Kamioka

A new experimental setup for low mass particle dark matter searches has been installed at the Kamioka underground facility, with an overburden of 2700 m.w.e. Ambient gamma and neutron background levels have measured. A dilution refrigerator is operational with gamma and neutron shielding under construction. Geant simulations predict backgrounds of 10 events/kg/keV/day with this setup. Multiple experiments are under preparation for g-yr level dark matter search exposures starting in mid 2025. These include superconducting targets read out with optical TES sensors and a test underground run of a TESSERACT Collaboration helium target payload. A status update will be provided.

Speaker: Maurice Garcia-Sciveres (Lawrence Berkeley National Lab. (US))

09:15 EXCESS backgrounds observed in low-threshold dark matter and CEvNS experiments

In the last years, rare event searches hunting light dark matter particles or neutrinos via coherent elastic neutrino-nucleus scattering (CEvNS) have pushed their thresholds down to eV-scales. However, with the lower thresholds, the experiments started to measure events above their expected background level. These low-energy EXCESSES typically steeply rise towards low energies and substantially constrain the experiments' sensitivity.

The EXCESS workshop series brings together the experiments and theorists to share data, knowledge, and ideas on the EXCESS to identify its origin and develop mitigation strategies. This contribution summarizes the current state of EXCESS based on a review article currently prepared by the authors.

Speaker: Florian Reindl (Vienna University of Technology (AT))

09:30 Searching for dark matter near and under the noise and backgrounds

The characteristic energy of a relic dark matter interaction with a detector scales strongly with the putative dark matter mass. Consequently, experimental search sensitivity at the lightest masses will always come from interactions whose size is similar to noise fluctuations and low energy backgrounds in the detector. In this talk, we will tackle this problem under two essential scenarios, the case when the potential signal rate is much lower than the effective bandwidth of the detector, and the case when the rate is higher.
In the low-rate scenario, individual signal events can be resolved and one needs to correctly calculate the net change in measured differential rate, accounting for both periods of time when the signal is coincident with noise/backgrounds and for the decreased amount of time in which only noise/backgrounds occur. We also show that introducing random events in the continuous raw data stream (a form of ``salting") provides a correct and practical implementation.
In the high-rate scenario, signal rate can be constrained with the shot noise power in a triggerless analysis. Particularly, in athermal phonon detectors, the DC noise power is limited by the thermal noise; correlated phonon shot noise, or equivalently the second moment of the baseline noise, can be limited by the cross spectrum density (CSD) with rejection to uncorrelated backgrounds; and finally the third moment of baseline noise gives more sensitivity to high energy signals.

Speaker: Xinran Li (Lawrence Berkeley national laboratory)

09:45 → 10:15 Coffee Break

10:15 → 11:50 SESSION 16- Directional Direct Detection & Direct Detection Recent Developments I

10:15 Directional Dark Matter Detection

The field of direct dark matter detection has recently entered the so-called neutrino fog, meaning that the most sensitive experiments are now detecting significant nuclear event rates caused by coherent scattering of solar neutrinos. Because the nuclear recoil directions for dark matter and neutrinos differ, new types of detectors capable of measuring these directions would have a powerful new handle for discriminating between dark matter and neutrino signals. Recoil directionality may also be key to demonstrating the galactic origin of a dark matter signal, and has several physics applications beyond dark matter.

I will review the field of directional recoil detection. I plan to cover the benefits of recoil directionality for dark matter detection, other physics applications unique to directional recoil detectors, different types of directionality, the performance requirements on directional detectors, recent detector R&D, and thoughts on the future of the field.

Speaker: Sven Vahsen (University of Hawaii (US))

10:35 Towards Quantum Sensing for Directional Dark Matter Detection Using Nitrogen Vacancy Centers in Diamond

Current detection methods for Weakly Interacting Massive Particle (WIMP) dark matter are approaching the so-called "neutrino fog," where irreducible background from solar neutrinos will obscure dark matter signals. To overcome this challenge, directional discrimination of events is critical. We propose developing a diamond-based particle detector that utilizes embedded quantum sensors to enable directional detection, supplementing conventional event registration techniques. When a WIMP or solar neutrino interacts with the diamond, it induces a nuclear recoil that leaves a permanent damage track measuring 10–100 nm. This track can be located and imaged using nitrogen-vacancy (NV) centers in diamond, leveraging advanced quantum sensing techniques. In this presentation, we will report recent progress in our group towards realizing a diamond-based directional dark matter detector, such as artificial track detection experiments via ion implantation, three-dimensional micron-scale strain imaging with a light-sheet quantum diamond microscope, and nanoscale strain imaging using super-resolution microscopy.

Speaker: Jiashen Tang (University of Maryland, College Park)

10:50 A step into the neutrino fog: first indication of solar CEvNS with XENONnT

The XENONnT detector, located at Laboratori Nazionali del Gran Sasso, in Italy, utilizes 5.9 tonnes of instrumented liquid xenon in the direct search for weakly-interacting massive particle (WIMP) dark matter. Having achieved unprecedented levels of target purity, it is sensitive to a plethora of signals beyond WIMPs. This talk will present an overview of the experiment and its perfomance in the search of solar B-8 neutrino interactions via the so-called coherent elastic neutrino-nucleus scattering (CEvNS) process. This analysis, pursued with a lower detection threshold than the standard WIMP search, yielded the first-ever solar CEvNS indication, with a statistical significance of 2.7σ.

Speaker: Diego Ramírez García (University of Zurich)

11:05 Effect of Ultralight Dark Matter on g-2 of the Electron

If dark matter is ultralight, the number density of dark matter is very high and the techniques of zero-temperature field theory are no longer valid. The dark matter number density modifies the vacuum giving it a non-negligible particle occupation number. For fermionic dark matter, this occupation number can be no larger than one. However, in the case of bosons the occupation number is unbounded. If there is a large occupation number, the Bose enhancement needs to be taken into consideration for any process involving particles which interact with the dark matter. Because the occupation number scales inversely with the dark matter mass, this effect is most prominent for ultralight dark matter. In fact, the Bose enhancement effect from the background is so significant for ultralight dark matter that, the correction to the anomalous magnetic moment is larger than experimental uncertainties for an effective coupling of of order 10−17 for a mass of order $10^{−20}$ eV if the dark matter is a dark photon or axion like particle. Furthermore, the constraint scales linearly with the dark matter mass and so new significant constraints can be placed on the dark matter mass all the way up to about $10^{−14}$ eV. Future experiments measuring $g-2$ will probe even smaller effective couplings.

Speaker: Prof. Jason Evans (Shanghai Jiaotong University/TDLI)

11:20 Exploring the keV scale spectrum of CUORE to Search for Solar Axions

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first tonne-scale experiment using cryogenic calorimeters. The detector is located underground at the Laboratori Nazionali del Gran Sasso in Italy and consists of 988 TeO2 crystals operated in a dilution refrigerator at a base temperature of about 10 mK. Thanks to the large exposure, sharp energy resolution, segmented structure and radio-pure environment, CUORE provided the most sensitive exclusion limit of the neutrinoless double beta decay of 130Te. The same features offer a unique opportunity to search for the interaction of dark matter candidates, such as Solar Axions, in the CUORE crystals. We are working towards demonstrating the potentiality of the CUORE detector technology in a lower energy region, from few to tens of keV, which is of interest for Solar Axion searches, and profit from the very large amount of data collected so far (2 ton yr of exposure) to search for these elusive dark matter candidates. In this contribution, we present a comprehensive study on low-energy events in the CUORE experiment, alongside the current status and future prospects in the search for Solar Axions.

Speaker: Dr Alberto Ressa (INFN Roma1)

11:35 The TRISTAN Detector Upgrade for the Search of Sterile Neutrino Dark Matter at KATRIN

The TRISTAN detector is an upgrade to the KATRIN experiment designed to optimize sensitivity to the spectral distortion caused by keV sterile states. The KATRIN experiment has produced the world leading limits from direct kinematic studies for the neutrino mass and eV scale sterile neutrinos through the precision measurement of the endpoint region of the tritium $\beta$ decay spectrum. After 1000 days of neutrino mass measurement, and the transition to a systematics dominated measurement, the KATRIN detector will be replaced by 9 TRISTAN detector modules to enable an efficient differential measurement of the full tritium spectrum. A statistical uncertainty of $\sin(\theta) < 10^{-6}$ is shown to be reachable in just 1 month of data taking in the new experimental configuration.

The production and characterization of the TRISTAN detectors, as well as the first tests of a partially populated TRISTAN tower with 3 detector modules in a KATRIN-like environment will be presented. The treatment of systematic effects to the spectral measurement, through response matrices and full Monte-Carlo approaches, is shown with the related impact to sensitivity to sterile mixing. Additionally, the changes in operating conditions within KATRIN and detector integration timeline to enable first TRISTAN data taking in 2026 is outlined.

Speaker: Andrew Gavin

11:50 → 12:50 Lunch Break

12:50 → 14:50 SESSION 17: Direct detection Recent Developments II & New Concepts

12:50 Direct Detection of Dark Matter Using Optically Levitated Nanospheres

Recent advances in levitated optomechanics have enabled the detection of tiny forces through precise control of microscopic objects in vacuum. These technologies present new experimental platforms to probe weakly coupled phenomena in particle and nuclear physics. I will describe a dark matter search based on optically trapped, femtogram-scale silica nanospheres. In ultra-high vacuum, the sensitivity of these levitated sensors is set by the quantum measurement noise, allowing the momentum transfer from a dark matter particle scattering from the sensor to be detected. For dark matter models that would primarily scatter from an entire nanoparticle (rather than a single nucleus or electron), these searches can exceed the sensitivity of even large underground detectors. I will further discuss applications of these sensors in precision measurement of nuclear decays and sterile neutrino searches.

Speaker: Yu-Han Tseng (Yale University)

13:05 Quantum Parity Detectors with meV resolution for low mass dark matter searches

Next generation "sub-GeV" dark matter searches require new tools and techniques with much improved sensitivity. In particular, the constrained kinematic space of potential interactions suggests that collective excitations like phonons may be the only signature of very low mass dark matter candidates. One promising technology to study these are qubit derived superconducting charge-parity sensors. These detection schemes include Quantum Capacitance Detectors (QCDs) and Offset-Charge Sensitive (OCS) devices, and the former have been demonstrated in previous literature as excellent far-IR photon counters with NEP of <1E-20 W/√Hz. We seek to extend the applicability of these techniques by directly coupling the sensors to interaction induced athermal phonons generated within a crystalline silicon substrate. Such a scheme will enable the literal counting of O(100) ueV quasiparticle quanta (broken Cooper-pair electrons) within a superconducting absorber, as produced by single meV phonons. In this presentation, we will discuss early results demonstrating a working charge-parity detector design, and lay out a roadmap for eV and subsequently lower energy resolution in future iterations.

Speaker: Karthik Ramanathan

13:20 GALILEO: Galactic Axion Laser Interferometer Leveraging Electro-Optics

We introduce GALILEO, a novel experimental approach to detect light dark matter candidates through precision optical interferometry. The method exploits the sensitivity of electro-optical materials, whose refractive indices are modulated by a coherently oscillating dark matter field. Using a high-precision resonant Michelson interferometer as the detection mechanism, GALILEO enables the exploration of uncharted parameter space for light dark matter, including dark photons and axion-like particles, across a broad mass range. Notably, the experiment achieves sensitivity to dark matter masses exceeding tens of microelectronvolts—a challenging regime for conventional microwave cavity haloscopes.

Speaker: Reza Ebadi

13:35 Searching for ultralight dark matter with trapped-ion interferometry

We explore how recent advancements in the manipulation of single ionic wave packets open new avenues for detecting weak magnetic fields sourced by ultralight dark matter. By leveraging the entanglement between the ion's spin and motional degrees of freedom, proposed trapped-ion matter-wave interferometers enable the measurement of the Aharonov-Bohm phase accumulated by the ion over its trajectory, which results in a parametric enhancement of the sensitivity to weak magnetic fields. Considering the relevant boundary conditions, we demonstrate that a single trapped ion can probe unexplored regions of dark photon dark matter parameter space in the $10^{-15}~\mathrm{eV} \lesssim m_{A'} \lesssim 10^{-14}~\mathrm{eV}$ mass window. We also show how these table-top quantum devices will serve as a complementary probe of axion-like particle dark matter in the same mass window.

Speaker: Leonardo Badurina (California Institute of Technology)

13:50 The Cross-Disciplinary Hunt for Dark Matter: Machine Learning and Material Science Meet Astroparticle Physics

The age of WIMP-like dark matter direct detection is drawing to a close due to their non-detection at exquisitely sensitive liquid-noble detectors. However, models where the dark matter is lighter than the mass of a proton remain largely inaccessible to existing probes. Recently, molecular targets have emerged as particularly well-suited detector materials to look for this sub-GeV dark matter. In this talk, I will show how theoretical techniques in chemistry and material science can be used to design searches that are sensitive to the best-motivated models of sub-GeV dark matter. I will review the latest development in molecule-based direct detection techniques and introduce how machine learning can be used to explore the vast and intractable space of potential materials, optimizing for theoretically-motivated electronic properties relevant to dark matter interactions. I will then present new constraints on sub-GeV dark matter from searches of molecular UV and IR signatures in gas and ice giants in the solar system. These astrophysical searches provide powerful new probes of unexplored parameter space and complement existing strategies for detecting dark matter.

Speaker: Carlos Blanco (Princeton University)

14:05 The QUAntum LImited PHotons In the Dark Experiment with far infrared photon counting

QUAntum LImited PHotons In the Dark Experiment (QUALIPHIDE) utilizes novel receivers and detectors operating in the microwave to far infrared to search of Hidden Photons (HP). Searches with quantum sensing techniques enables exploring new phase space for both HPs and axion like particles as candidates for dark matter. The first version of QUALIPHIDE was done in the microwave with traveling wave parametric amplifiers. Now, we are pursuing deeper than standard quantum limit searches with photon counting. This new iteration of QUALIPHIDE will operate in 8-16 THz (~50 meV hidden photon masses), with expected sensitivity of kinetic mixing $\gtrsim 10^{-12}$. The sensors will be the focus, as we enable their reach with mHz dark count rates, and eventually towards ~1 THz.

Speaker: Ritoban Basu Thakur

14:20 Turn off the lights to see hidden sector dark matter

Dual-phase liquid xenon TPCs have the potential to discover sub-GeV dark matter. In this low-energy regime, the limiting background is due to the instrument itself in the form of delayed electron and photon emission. In this talk, we present new data explaining the mechanism for delayed emission. Furthermore, we describe steps towards a prototype xenon TPC with significantly reduced delayed emission rates. We conclude with an outlook on plans for a competitive xenon TPC for low-mass dark matter searches.

Speaker: Ryan Gibbons (UC Berkeley)

14:35 CMB-S4 Talk

To be submitted

Speaker: Kimberly Boddy

14:50 → 15:20 Coffee Break

15:20 → 18:05 SESSION 19: Direct detection: Ultra-Light DM (Axions, ALPs, WISPs) searches

15:20 Recent results on dark sector searches at Belle II

The Belle II experiment has unique reach for a broad class of models that postulate the existence of dark matter particles with MeV—GeV masses. This talk presents recent world-leading physics results from Belle II searches for Z' bosons, axion-like particles, and dark scalars in association with two muons in e+e- collisions; long-lived (pseudo)scalars produced in decays of B-mesons; inelastic dark matter; as well as the near-term prospects for other dark-sector searches.

Speaker: Steven Robertson (IPP / University of Alberta)

15:35 Searching for Axion Dark Matter with the ORGAN Experiment

located at the University of Western Australia in Perth, Australia, the ORGAN (Oscillating Resonant Group AxioN) experiment is a microwave cavity axion haloscope that searches for axions in the 15–50 GHz mass range from the putative axion-photon coupling term g_agg , which began in 2017 [1]. The experiment has undergone several experimental runs, which will be detailed in this presentation [1-5]. We have also undertaken and proposed several experiments in lower mass ranges [5,6], including experiments that search for extra axion-photon coupling terms, g_EM and g_MM , if the high-energy magnetic monopole exists [5-9], which will also be detailed in this presentation.

Speaker: Michael Tobar

15:50 The Axion Dark Matter eXperiment (ADMX): Overview of Current Operations and Future R&D

The Axion Dark Matter eXperiment (ADMX) is a direct-detection axion dark matter search operating as one of the Department of Energy (DOE) "Generation 2" dark matter projects. ADMX searches for dark matter axions in the micro-eV mass range using a large (V ~ 100L) high-Q (Q ~ 40,000) electromagnetic cavity threaded by a moderate intensity magnetic field (B ~ 8T) to resonantly convert local halo axions into microwave photons via an inverse-Primakov channel of the candidate. The cavity haloscope technique aided by a low-noise amplifier chain has enabled ADMX to approach standard quantum limit (SQL) noise and reach sensitivities surpassing both the Kim-Shifman-Vainshtein-Zakharov (KSVZ) and Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) benchmark models. This talk will provide an overview of ADMX's current Run 1 operations (0.64-1.3 GHz, 2.65-5.4 $\mu$eV) and upcoming Run 2 (1.25-2.25 GHz, 5.2-9.3 $\mu$eV) and Extended Frequency Range searches (2-4 GHz, 8.3-16.6 $\mu$eV) for which the single cavity will be replaced by four and eighteen cavities respectively, as well as R&D efforts to further the frequency range beyond 4 GHz, improve operational efficiency, and improve sensitivity beyond the SQL.

Speaker: Erik Lentz (Pacific Northwest National Laboratory)

16:05 New Results from HAYSTAC's Search for Dark Matter Axions

The Haloscope At Yale Sensitive To Axion CDM (HAYSTAC) experiment is a microwave cavity search which is actively probing QCD axions with masses ≳$10\mu$eV. In this talk, I will present recent results from HAYSTAC's Phase II search for QCD axions between $16.96-19.46\mu$eV. These results are the widest search to date to achieve a quantum enhanced scan rate from a squeezed state reciever and include new data covering $1.71\mu$eV of previously unexplored parameter space with sensitivity to QCD axions with axion-photon coupling of $\sim3\times$$|g^{KSVZ}_{\gamma}|$. I will also discuss upgrades in development to facilitate further searches for axions beyond $20\mu$eV.

Speaker: Michael Jewell (Yale University)

16:20 The progress of ALETHEIA, a low-mass DM direct detection project with liquid helium-filled TPCs

ALETHEIA, standing for A Liquid hElium Time projection cHambEr In dArk matter, is a newly established direct detection project aiming to search for low-mass DM with liquid helium-filled time projection chambers (TPCs). The project was officially launched in 2020 and has made significant progress since then. In this talk, I will mainly demonstrate that a single-phase liquid helium (LHe) TPC is technologically viable; moreover, I will slightly discuss some of the challenges in building a dual-phase LHe TPC and the preliminary solutions.

Speaker: Junhui Liao

16:35 Searching for Axions and High-Frequency Gravitational Waves with ABRACADABRA-10cm

ABRACADABRA-10cm has had great success as a lumped-element axion dark matter pathfinder experiment. Now, using the electrodynamics of gravitational waves and a simple change of pickup structures, we are using the ABRACADABRA detector to search for high-frequency gravitational wave in the kHz to MHz range. These higher frequencies may indicate signs of in-spiraling primordial black holes, or other beyond the standard model phenomena. With careful calibration and simulation used to distinguish between the two signals, we introduce the first simultaneous search for both axions and gravitational waves. I will present on the design and results from the ABRACADABRA-10cm high-frequency gravitational wave search.

Speaker: Dr Kaliroe Pappas (Columbia University)

16:50 NuSTAR as an Axion Helioscope

We present a novel approach to investigating axions and axion-like particles (ALPs) by studying their potential conversion into X-rays within the Sun’s atmospheric magnetic field. Utilizing high sensitivity data from the Nuclear Spectroscopic Telescope Array (NuSTAR) collected during the
2020 solar minimum, along with advanced solar atmospheric magnetic field models, we establish a new limit on the axion-photon coupling strength gaγ ≲ 6.9 × 10−12 GeV−1 at 95% confidence for axion masses ma ≲ 2 × 10−7 eV. This constraint surpasses current ground-based experimental limits, opening previously unexplored regions of the axion-photon coupling parameter space up to masses of ma ≲ 5×10−4 eV. These findings mark a significant advancement in our ability to probe axion properties and strengthen indirect searches for dark matter candidates.

Speaker: Prof. Jaime Ruz Armendariz (TU Dortmund)

17:05 DMRadio: The Search for < 1μeV Axions

The nature of dark matter remains one of the greatest open questions in physics. The DMRadio program focuses on axions with masses below 1 μeV, a highly motivated parameter space linked to GUT-scale physics and dark matter produced before inflation. Exploring this regime presents unique challenges, requiring large magnets and precision sensing techniques that push beyond the Standard Quantum Limit (BSQL). In this talk, I will discuss the strong motivation for these axions and outline DMRadio’s staged strategy for a definitive search: DMRadio-50L, DMRadio-m3, and DMRadio-GUT.

Speaker: Lindley Winslow

17:20 Design and development of the Princeton Axion Search

The Princeton aXion Search (PXS) is a new experiment to search for QCD axion dark matter in the 0.8-2.1 ueV mass range (corresponding to 200-500 MHz frequency range). I describe development into all aspects of the experiment, including solenoidal magnet, cryogenics, amplifiers, and resonators. PXS leverages a strong partnership with the Princeton Plasma Physics Laboratory (PPPL) to build a 5T, 0.5 m^3 conduction-cooled Nb3Sn magnet. PXS is also working with Caltech/JPL to build near-quantum-limited parametric amplifiers tailored to this frequency range. I present the design for the full-scale experiment, which is under construction, as well as results from preliminary tests of a model coil, room-temperature cavity prototype, and kinetic inductance traveling-wave parametric amplifier.

Speaker: Joelle-Marie Begin (Princeton University)

17:35 BREAD- The Broadband Reflector Experiment for Axion Detection

The BREAD Collaboration is conducting R&D towards wide band dish antenna searches for axions using a unique coaxial antenna design which is well suited for deployment in large solenoid magnets and compatible with sub-kelvin detectors. We will discuss the overall BREAD (Broadband Reflector Experiment for Axion Detector) program and its technology development, focusing on plans for detectors in the THz and infrared regions of the spectrum. Future experiments are being planned to share the use of a large-bore 9.4 Tesla MRI magnet recently acquired by Fermilab for the ADMX-EFR project.

Speaker: Andrew Sonnenschein (Fermilab)

17:50 Overview and Current Status of GRAMS (Gamma-Ray and AntiMatter Survey)

GRAMS (Gamma-Ray and AntiMatter Survey), one of the NASA Physics of the Cosmos missions, is a balloon-borne experiment utilizing a LArTPC (Liquid Argon Time Projection Chamber) detector that is potentially expandable to a future satellite mission. GRAMS aims for both MeV gamma-ray observations and antimatter-based indirect dark matter searches. With a low-cost, large-scale LArTPC detector, GRAMS can provide significantly improved sensitivities to gamma rays in a historically under-explored energy regime often referred to as the MeV Gap. GRAMS can also extensively probe a new dark matter parameter space via low-energy antinuclei measurements, including the regions suggested by the Fermi GCE (Galactic Center Excess) and AMS-02 antiproton excess. We had a successful engineering balloon flight in Japan in 2023 to demonstrate the LArTPC operation in the stratosphere. We are currently preparing for the prototype balloon flight (pGRAMS) from Tucson, Arizona, in late 2025 or early 2026 using a LArTPC that is smaller-scale but still one of the largest Compton telescopes. In this talk, I will present an overview and current status of the GRAMS project.

Speaker: Tsuguo Aramaki

18:05 → 18:35 SESSION 20: Final talk