IDM 2024

8 Jul 2024, 08:00 → 12 Jul 2024, 20:00 Europe/Rome

L'Aquila, Italy

Alfredo Davide Ferella (Istituto Nazionale di Fisica Nucleare), Natalia Di Marco (Istituto Nazionale di Fisica Nucleare), Paolo Gorla (Istituto Nazionale di Fisica Nucleare)

This is the Indico site for the 15th International Workshop on the Identification of Dark Matter that will take place in L'Aquila, Italy. 
This website was created for the abstract submission and the review process. All other information and tools are available on the official website of IDM2024: www.idm2024.eu

Monday, 8 July

08:30 → 09:00 Registration

IDM-wifi.pdf

09:00 → 10:30 Plenary

Convener: Natalia Di Marco (Istituto Nazionale di Fisica Nucleare)

09:00 Welcome

IDM2024_Wellcome.pdf

Monday_locations.pdf

09:30 Dark matter searches: status and prospects

Abstract: In the latest decades, the approaches towards investigating the nature of the dark matter component of the Universe have been marked by prejudices, mostly in connection to: A natural embedding of dark matter into an extension to the Standard Model of particle physics, possibly as a byproduct within models addressing some shortcoming of the Standard Model; A natural mechanism to produce dark matter in the early Universe, possibly in analogy to the other components defining the Standard Model of cosmology. Our faith in elegance and simplicity is fading away with results from accelerators searches and cosmological tensions. Conversely, a picture with a variegated, multi-component dark sector is becoming more plausible, breaking prejudges and opening new windows of opportunities.

Speaker: Piero Ullio (SISSA, Trieste)

IDM-2024-ullio.pdf

10:00 Experimental status of the cosmological standard model

This talk will detail the experimental status of the cosmological standard model. It will cover the recent joint analyses from the Pantheon+ & SH0ES collaborations and that tell two important stories. The Pantheon+ supernova constraints of cosmic acceleration are the current best measurement of the dominant energy density components of the universe and provide strong constraints on potential modifications to Lambda Cold Dark Matter (LCDM) model. Meanwhile, I will detail how SH0ES cosmic distance ladder measurement is now even more robust to systematic uncertainties and has crossed the significant threshold of 5-sigma discrepancy when compared to the cosmic microwave background (Planck) under the assumption of a LCDM model. The talk discusses the original treatment and now new testing of systematic uncertainties, numerous additional datasets that independently corroborate the tension, and additional techniques that shed light on the source of the tension.

Speaker: Dillon Brout (Boston University)

Experimental status of the standard cosmological model.

10:30 → 11:00 Coffee break

11:00 → 12:30 Plenary

Convener: Fabrizio Nesti (Istituto Nazionale di Fisica Nucleare)

11:00 Status and Inconsistencies in the Standard LCDM Model: a theoretical cosmologist perspective

In this talk I will give an overview of the status of the Standard LCDM model, from the perspective of a theoretical cosmologist. After a brief overview of the model itself and its fundamental pillars and assumption, I will briefly describe a selection of the very large number of alternatives proposed. Returning to LCDM, this is based on General Relativity (GR), but when it comes to study nonlinear structure formation we use Newtonian simulations. Thus I will focus on the specific problem of understanding gravity on cosmological scales, on the largest ones where perturbative methods can be applied, to the smaller nonlinear scales of clusters and galaxies, down to supermassive black holes.

Speaker: Marco Bruni (University of Portsmouth)

L'Aquila_IDM_2024.pdf

11:30 A new Paradigm and new Scenarios for the Dark Matter Phenomenon.

The phenomenon of the Dark Matter baffles the researchers: the underlying dark particle has escaped so far the detection and its astrophysical role appears complex and unexpectedly related with that of the Standard Model (luminous) particles. We propose that, in order to act efficiently, alongside with abandoning the current ΛCDM scenario, we need also to shift the Paradigm from which such scenario has emerged. In detail, the simplicity, the usefulness in shedding light on some other well-known problem of fundamental physics, so as a strong degree of falsiability, a promising dark particle detectability in experiments and observations and the emergence of a new channel of investigation via Cosmological computer simulations, all cease, according to the new Paradigm, to be necessary features of the correct DM scenario. To get the latter, instead, we propose that highest priority should be given to the information coming from the entanglement between the dark and the luminous matter, observed in virialized systems like galaxies and clusters.

Speaker: Paolo Salucci (SISSA)

aquila.pdf

12:00 Gaia as local cosmological probe

The ESA mission Gaia is providing a detailed reconstruction of our Milky Way enabled through microarcsecond global astrometry.
At such level of accuracy, a fully general relativistic analysis of photon trajectories from the observational data back to the space-time origin of the emitting astronomical object is mandatory. This necessarily implies the dismissal of Newtonian straight lines and the adoption of a suitable general relativistic measurement ‘toolkit’.
Then, ultimately, from Gaia onwards, high accurate measurements must include General Relativity at the very core of the data analysis to guarantee the scientific quality. Indeed, gravitational astrometry offer the unique possibility of establishing a laboratory for extensively testing the role of Milky Way in gravity theories, in other words a coherent frame to probe our whole Galaxy as the product of cosmological evolution shaped by gravity (Local Cosmology), i.e. the relations among baryonic structures (and their evolution) and the Universe dark components.
In this respect, the talk will discuss of the attempts at applying the accurate relativistic kinematics recently delivered by Gaia to trace the Milky Way rotation curves, focusing on the latest results obtained by comparing an exact general relativistic approach to (Λ)CDM and MOND analogues. Close to 1 million of Gaia-only sources have been selected according to the requirements for a proper 6-dimensional reconstruction of the phase-space location occupied by each individual star. The likelihood analysis shows that the different models appear equally consistent with the data and confirms, a posteriori, the hypothesis of validity of a relativistic model for the Milky Way. In brief, our findings tell that, the gravitational dragging deduced from the Einstein field solution could mimic a “DM” or MOND effect for the observed flatness of the Galactic rotational curve.

Speaker: Mariateresa Crosta

Gaia_as_Local_Cosmological_probe_Crosta.pdf

12:30 → 14:00 Lunch

14:00 → 16:00 Parallel 1: Direct detection

Convener: Carla Macolino (Istituto Nazionale di Fisica Nucleare)

14:00 PandaX-4T Experiment and its Recent Progress on WIMP search

PandaX-4T is a several-tonne-scale dark matter direct searching experiment, utilizing 4 tonne liquid xenon as target material in sensitive volume. The experiment is located at China Jinping Underground Laboratory, with overburden of 2400 meter water equivalent. In 2021, the PandaX-4T experiment has released its first data and obtained various search result at the time. In this talk, I will introduce the recent results of PandaX-4T experiment on the WIMP search with newly obtained data.

Speaker: Qing Lin (University of Science and Technology of China)

PandaX_Talk_v4.pdf

14:20 WIMP Dark Matter searches with the XENONnT experiment

The XENONnT experiment is aiming for the direct detection of dark matter in the form of weakly interacting massive particles (WIMPs) using a liquid xenon (LXe) time projection chamber. The detector, operated at Laboratori Nazionali del Gran Sasso (LNGS) in Italy, features a total LXe mass of 8.5 tonnes of which 5.9 tonnes are active. XENONnT has already completed its first science run and is continuing taking science data. It has achieved an unprecedented purity for both, electronegative contaminants, with an electron lifetime exceeding 10 ms due to a novel purification in liquid phase, and for radioactive radon, with an activity of 1.72±0.03 𝜇Bq/kg due to a novel radon distillation column.
This talk will present the latest results from the search for nuclear recoils induced by WIMPs using data from the first science run with an exposure of 1.1 tonne-year. In addition, results from other searches for non-standard interactions and new particles via their electronic interactions will be shown.

Speaker: Henning Schulze Eißing

XENON_WIMP_Talk_at_IDM.pdf

14:40 An update on the LUX-ZEPLIN (LZ) experiment’s search for dark matter

The LUX-ZEPLIN (LZ) experiment is actively collecting physics data in the search for WIMP dark matter and other novel physics interactions nearly a mile underground at the Sanford Underground Research Facility. LZ achieves an unprecedented sensitivity for discovering WIMP-nucleon interactions by employing a low-background, 7-tonne liquid xenon time-projection chamber surrounded by a three-component veto system: a liquid-xenon skin, a nearly-hermetic Gd-loaded liquid scintillator, and an instrumented tank of ultra-pure water. In this talk I will present the status of the LZ experiment and its search for WIMP dark matter and other new physics phenomena.

Speaker: Ibles Olcina

IDM_2024_IO_v2.pdf

15:00 Accidental Coincidence Background in XENONnT for Low Energy Nuclear Recoil Search

Solar neutrinos can interact with liquid xenon (LXe) dark matter detectors through coherent elastic neutrino-nucleus scattering (CEvNS), producing signals similar to DM-nucleus interactions. Known as the 'neutrino fog,' this phenomenon significantly challenges direct dark matter detection efforts. The XENONnT detector, noted for its substantial exposure and low background, provides a prime opportunity to probe this interaction.
This presentation will detail the analysis of the first and second science runs of XENONnT to search for Solar B8 CEvNS signals. We employed novel low-threshold analysis techniques, including suppression of the dominant accidental coincidence backgrounds and modeling of the multidimensional signal and backgrounds in statistical inference, to significantly enhance the sensitivity to solar B8 neutrinos.

Speaker: Kexin Liu (Tsinghua University)

IDM2024_XENONnT_AC_v6_kexin.pdf

15:20 Recent status and prospects of CDEX dark matter search at CJPL

The CDEX program pursues the direct detection of light dark matter candidates with an array of germanium detectors since 2009 at the deepest operating underground site, China Jinping underground laboratory (CJPL) located in Sichuan, China, with a rock overburden of about 2400m. Searches of modulation effect of light WIMPs, WIMPs-nucleus interaction via Midgal effect, dark photon model, solar axions and axion-like particles have been recently carried out based on the CDEX-1 and CDEX-10 experiments. An upgraded dark matter experiment of the CDEX-50 is proposed and on-going together with the R&D programs on many key low radioactivity technologies. Results and the prospects of the CDEX dark matter program will be described and discussed.

Speaker: Litao Yang (Tsinghua University)

20240708_CDEX Status_YangLT@IDM2024 - final.pdf

15:40 The PICO-40L Direct Detection Experiment

Constraining the spin-dependent WIMP-nucleon cross-section using Earth-based direct detection experiments is a critical component of the ongoing effort to discover the nature of dark matter. PICO-40L is a bubble chamber detector with a target material of superheated C₃F₈, located at the SNOLAB underground research facility outside Sudbury, Canada. In bubble chambers, since energy depositions from particle interactions are required to be sufficiently localized in order to nucleate a bubble, PICO-40L is effectively blind to electron recoil interactions, which is a major class of background in other direct detection technologies. PICO-40L is the first dark-matter-sensitive PICO experiment to employ the "Right Side Up" geometry, putting the detector compression and expansion system below the target fluid, which is expected to suppress backgrounds seen in previous PICO detectors. With its abundance of non-zero-spin fluorine nucleons in the detector target, it has the capacity to set world-leading exclusion limits in the spin-dependent dark matter interaction parameter space. PICO-40L is fully assembled and operational, and is currently being commissioned. An overview of the detector, the analysis strategy, as well as the results from the early commissioning runs, will be presented in this talk.

Speaker: Derek Cranshaw (Queen's University)

The_PICO-40L_Direct_Detection_Experiment_DerekCranshaw.pptx

14:00 → 16:00 Parallel 2: Cosmology Dark Matter

Convener: Luigi Pilo (Istituto Nazionale di Fisica Nucleare)

14:00 Minimal Dark Matter Freeze-in with Low Reheating Temperatures and Implications for Direct Detection

In this presentation, I will investigate the influence of the reheating temperature of the visible sector on the freeze-in dark matter (DM) benchmark model for direct detection experiments, where DM production is mediated by an ultralight dark photon. I will consider a new regime for this benchmark where the initial temperature of the thermal Standard Model (SM) bath to be below the DM mass. The production rate from the SM bath is drastically reduced due to Boltzmann suppression, necessitating a significant increase in the portal coupling between DM and the SM to match the observed relic DM abundance. This enhancement in coupling strength increases the predicted DM-electron scattering cross section, making freeze-in DM more accessible to current direct detection experiments.

Speakers: Barmak Shams Es Haghi (University of Texas at Austin), Gabriele Montefalcone (University of Texas at Austin)

IDM_gabriele_montefalcone.pdf

14:20 Feedback in the dark: a critical examination of CMB bounds on primordial black holes

Primordial Black Holes (PBHs) may exist, possibly contributing to the Dark Matter abundance. We will revisit some key aspects of the cosmological bound on a subdominant population of heavy PBHs, originating from the accurate measurement of the anisotropies in the Cosmic Microwave Background (CMB). We will analyze the role of accretion physics, with particular focus on the interplay between the radiation feedback and the “accretion boost” provided by the bulk of the dark matter that cluster around PBHs and form mini-halos. We will demonstrate that the local increase in temperature around PBHs provided by the radiation emitted by the accreted matter can prevent the dark matter mini-halos from strongly enhancing the accretion process, in some cases significantly weakening previously derived CMB constraints. In the last part of the talk, we also review other uncertainties in the bound under scrutiny and provide a comprehensive assessment on the robustness of the bound.

Speaker: Daniele Gaggero (Istituto Nazionale di Fisica Nucleare)

IDM_DG.pdf

14:40 The JWST lensed quasar dark matter survey

Strong gravitational lensing provides a direct, purely gravitational method to infer the properties of dark matter halos and thereby constrain the mass, formation mechanism, and possible self-interactions of the dark matter. Many strong lenses appear as four lensed images of a background quasar alongside spatially-resolved light from the quasar host galaxy that we observe as spectacular, extended lensed arc(s). I will discuss how simultaneous reconstruction of the relative magnifications of quasar images and lensed arcs places stringent constraints on the deflection field of the lens system, isolating the subtle lensing signatures associated with low-mass (M < 10^8 solar mass) dark matter halos from properties of the lens on larger scales. I will discuss implications for models of warm and self-interacting dark matter, theories in which these low-mass halos exist in lower numbers as a result of free-streaming, or have extremely high central densities after experiencing “gravothermal catastrophe”, or core collapse, as a consequence of dark self-interactions.

Speaker: Daniel Gilman (University of Chicago)

gilman_pres_pdf.pdf

gilman_pres_v2.key

15:00 Constraining Self-interacting Scalar Field Dark Matter with Strong Gravitational Lensing

The most widely accepted model to describe our Universe is the Cold Dark Matter model (CDM), where the WIMPs scenario is favored for theoretical and experimental reasons. However, despite many experiments, WIMPs have still not been detected. Moreover, as observations and simulations at galactic scales have improved, several challenges remain such as the core-cusp problem and the missing satellite problem.

These tensions could be signs of new physics needed to better understand our Universe. In this context, alternative scenarios have emerged including the hypothesis that DM could be a scalar field (SFDM) with masses ranging from 10^(-22) eV to eV.

This ultra-light mass corresponds to a de Broglie wavelength on the parcsec or kiloparsec scale. Consequently, at scales much smaller than this wavelength, the field exhibits wave-like behavior. These dynamics will result in a different density distribution of dark matter compared to the Navarro-Frenk-White (NFW) profile that typically characterizes CDM halos.

In this talk, I will discuss the use of strong gravitational lensing within galaxy clusters to test SFDM models, in particular the self-interacting model. Gravitational lensing is a powerful technique for investigating mass distribution in dense regions like galaxy clusters. By analyzing gravitational lensing effects, we can place constraints on the parameter space of the model such as the scalar field mass and interaction strengths. Moreover, I will discuss the impact of the baryons in these configurations.

Through a combination of theoretical and numerical calculations and observational data analysis, we investigate how SFDM modifies gravitational lensing patterns compared to the CDM model. Our findings provide valuable insights into the alignment of SFDM with observational data, thereby enhancing our understanding of the mysterious properties of dark matter.

Speaker: Raquel Galazo Garcia (Laboratoire d'Astrophysique de Marseille, Aix-Marseille Université, CNES, CNRS)

GALAZO_IDM_2.pdf

15:20 Testing Primordial Black Holes Dark Matter with Galaxy Catalogs cross-correlations

Some of the gravitational-wave (GW) events detected by LIGO-Virgo might be black holes of primordial origin. However, unveiling the origin of these events is challenging, notably if no multi-wavelength counterpart is detected.
One important diagnostic tool is the coalescing binary distribution with respect to the large scale structures (LSS) of the universe, which we quantify via the cross-correlation of galaxy catalogs with GW ones. We test the discrimination power of this tool by using both existing and forthcoming galaxy catalogs and using realistic Monte Carlo simulations of GW events. We find that, provided enough observation time, already the current generation of GW detectors has the sensitivity to discriminate between primordial and astrophysical black holes.
The third generation GW detectors such as the Einstein Telescope or the Cosmic Explorer will then allow one to perform precision studies of the coalescing black hole LSS distribution and attain rather advanced model discrimination capabilities.

Speaker: Alessandro Cuoco (Istituto Nazionale di Fisica Nucleare)

IDM_LAquila_July2024.pdf

15:40 Constraining dark matter models using dwarf galaxy size and luminosity

The small-scale structure within the Galactic dark matter halo offers a variety of opportunities to test the nature of dark matter, which can be traced by galaxy observations. In particular, models that enhance or suppress the formation of structure will affect the abundance and concentration of dark matter halos. This leads to a distinct signature in local dwarf galaxy observations. 
In particular, we use the observed relation between the size and luminosity of dwarf galaxies to test dark matter models. By combining high resolution numerical simulations with galaxy formation models, we model galaxies and compare them with observations. The differences among dark matter models considered in our work are characterized through a tilt in the matter power spectrum. In this talk, I will discuss constraints on the matter power spectrum down to very small scales of $k$~100 Mpc$^{-1}$, improving on all current measurements at these scales.

Speaker: Ariane Dekker (KICP, University of Chicago)

IDM_AD_0.pdf

14:00 → 16:00 Parallel 3: Axion/Sterile

Convener: Giovanni Benato (Istituto Nazionale di Fisica Nucleare)

14:00 HAYSTAC Status and Future Plans

The HAYSTAC experiment (Haloscope At Yale Sensitive To Axion Cold dark matter) has operated for a decade both as a data pathfinder for the 4-12 GHz (~16-50 $\mu$eV) range, and a testbed for new resonator and amplifier technologies. Final results will be presented for Run II which incorporated a Squeezed-State Receiver to circumvent the Standard Quantum Limit, the first dark matter experiment to do so. Runs III and IV will search at higher frequencies using tunable lattice resonators, and further accelerate the scan rate with a receiver based on two-cavity entanglement and state-exchange, for which an order-of-magnitude is projected. The development and operational experience of these innovations prepare for the larger ALPHA experiment to search for the post-inflation axion in the 10-20 GHz (~40-80 $\mu$eV) range, currently under construction at Yale.

Support is gratefully acknowledged by the National Science Foundation under Grants No. PHY-1701396, No. PHY-1607223, No. PHY-1734006, No. PHY-1914199, and No. PHY02209556.

Speaker: Karl van Bibber (University of California Berkeley)

• IDM 2024 - HAYSTAC.pdf

14:17 High Frequency Microwave Cavity Design Innovations for Axion Dark Matter Searches

The most sensitive searches for axion halo dark matter are based on the resonant conversion of axions to photons in a microwave cavity permeated by a strong magnetic field. Current and future experiments such as HAYSTAC and ALPHA seeking to reach recent predictions of the post-inflation axion of masses of 40-180 μeV (~10-45 GHz) are challenged both by the rapidly diminishing volume of conventional microwave cavities with frequency (thus loss of signal power) and by the proliferation of other modes which hybridize with the mode of interest (thus loss of frequency coverage). We will present the design and first experimental results of metamaterial-inspired resonators which can simultaneously have the requisite high frequency and large volume, and on photonic band gap structures which can trap the mode of interest (TM010) while radiating away most of the interfering modes (TElmn). These results informed design choices for both HAYSTAC run III and ALPHA run I. HAYSTAC will employ a symmetric multi rod resonator covering a frequency range of 6.3-8.6 GHz. ALPHA run Ia will apply a similar approach to create a resonator aimed at the 10-20 GHz range, and ALPHA run Ib will use a more optimized though mechanically complex design.

Speaker: Heather Jackson (UC Berkeley)

JACKSON IDM2024.pptx

14:34 The ALPHA axion dark matter experiment

Among the possible dark matter candidates, axions are one of the most promising. Yet, the parameter space allowed by theory is considerably unexplored. Cutting-edge calculations favor post-inflation axion mass of tens of μeV. This corresponds to roughly 10-100 GHz in frequency, too high for conventional haloscopes to reach. The Axion Longitudinal Plasma Haloscope (ALPHA) located at Yale University is a new concept of detector. It makes use of materials arranged in a clever fashion (metamaterials) to engineer a custom plasma and probe the 10-45 GHz frequency range. This talk will describe the general design of the experiment, the current status of the R&D, and the expected sensitivity.

Speaker: Andrea Gallo Rosso

IDM2024_Gallo_Rosso.pdf

14:51 QUAX: Probing Axion Dark Matter through quantum technologies

The QUest for Axion (QUAX) is a direct-detection CDM axion search which reaches the sensitivity necessary for the detection of galactic QCD-axion in the range of frequency 8.5-11 GHz.

The QUAX collaboration is operating two haloscopes, located at Padova/LNL- and LNF-INFN laboratories in Italy, that work in synergy and operate in different mass ranges.

In this talk we will report about results obtained at the Padova-LNL laboratories , using a high quality factor dielectric cavity cooled at less than 100 mK inside a dilution refrigerator equipped with a 8 T magnet with a JPA and TWPA-based amplification chain for cavity signal readout, resulting in a system noise temperature at the quantum limit.

Results will presented for the axion-electron and axion-photon coupling around the 10 GHz frequency range.

We will also report about R&D activity aimed at increasing the scanning speed with application of transmon-based single microwave photon detectors (SMPDs) for cavity readout.

The prototype haloscope we developed is based on a cylindrical copper cavity sputtered with NbTi, resonant at 7.3 GHz frequency, and cooled at mK temperatures inside a dilution refrigerator equipped with a SC magnet.

Results obtained employing a moderate magnetic field will be described.

Speaker: Giovanni Carugno (Istituto Nazionale di Fisica Nucleare)

IDM24.pdf

15:08 BREAD: Broadband Reflector Experiment for Axion Detection

We report on the status of BREAD - a novel dish antenna for broadband ~$\mu$eV-eV wave-dark matter detection, which allows to utilize state-of-the-art high-field solenoidal magnets. Axions are converted non-resonantly to photons on a cylindrical metallic wall parallel to an external magnetic field. These photons are then focused using a novel reflector geometry onto a state-of-the-art high-sensitive photon detector. We recently demonstrated [PRL 128 (2022) 131801] that this concept using a $\sim 10\,{\rm m}^2$ conversion area in a $\sim 10\,{\rm T}$ solenoidal magnet has the potential to discover QCD axions spanning multiple decades in mass range. In this talk we present progress of our first stage pilot experiments - GigaBREAD [PRL 132 (2024) 131004] and InfraBREAD - covering different mass ranges. We outline the status of current R&D and recent results. We discuss upscaling to larger, cryogenic and magnetized versions as well as a new 9T large-bore magnet facility at Fermilab to realize such experiments - the Dark Wave Laboratory.

Speaker: Stefan Knirck (Fermi National Accelerator Laboratory)

knirck_stefan_bread_compressed.pptx

15:26 The axion dark matter experiment MADMAX

The MAgnetized Disk and Mirror Axion eXperiment is a future experiment aiming to detect dark matter axions from the galactic halo by resonant conversion to photons in a strong magnetic field. It uses a stack of dielectric disks, called booster, to enhance the axion-photon conversion probability over a significant mass range. Several smaller scale prototype systems have been developed and used to verify the experimental principles. This talk will present the current status of the experiment and its prototypes, including the ongoing research and development and first limits on dark photon dark matter.

Speaker: Jacob Egge (University of Hamburg)

MADMAX_IDM_2024_JE

15:43 Searching for sub-μeV axions with DMRadio: Overview and Status

The QCD axion is a promising dark matter candidate whose discovery would also solve the Strong CP problem of particle physics. The DMRadio suite of experiments, which consists of DMRadio-50L, DMRadio-m$^3$, and DMRadio-GUT, are designed to be sensitive to QCD axions in the peV to $\mu$eV mass range. Axions in this mass range may be produced in the measured dark matter abundance in the early universe if Peccei-Quinn symmetry breaking occurred prior to inflation. However, state-of-the-art searches for axions using resonant cavities cannot probe axions in this mass range because the axion’s Compton wavelength is very large compared to the size of the detector. Therefore, the DMRadio suite of experiments uses lumped-element LC resonators to decouple the resonance frequency from the physical size of the detector. DMRadio-50L probes axions in the 100 kHz to 5 MHz range and is nearing construction completion. DMRadio-m$^3$ is sensitive to the DFSZ axion model within 30 MHz-200 MHz, is sensitive to the KSVZ axion model within 10 MHz-30 MHz, and its design is nearing completion. Here we present an overview of the design and status updates of DMRadio-50L and DMRadio-m$^3$.

Support from the Gordon and Betty Moore Foundation is gratefully acknowledged.

Speaker: Alexander Droster (University of California, Berkeley)

IDM 2024_droster2.pptx

IDM 2024_droster4.pdf

16:00 → 16:30 Coffee break

16:30 → 18:50 Parallel 1: Direct detection

Convener: Paolo Agnes (GSSI)

16:30 Status of DEAP-3600 experiment

DEAP-3600 operates as a dark matter direct detection experiment situated at the SNOLAB facility in Sudbury, Canada. The spherical detector, positioned 2 km beneath the earth's surface, operates within a low cosmic muon background environment. It comprises 3.3 tonnes of liquid argon target encircled by an array of 255 photomultiplier tubes. DEAP-3600 encounters significant background sources primarily emanating from alpha particles generated by its components and dust particles within the detector, external neutrons, and beta decays of Argon-39. This presentation will cover the most recent findings from DEAP-3600, including advancements in developing a detailed background model, pulse-shape discrimination techniques, and enhancing the sensitivity to dark matter. Additionally, I will provide an overview of the ongoing research and development projects aimed at hardware upgrades.

Speaker: Pushparaj Adhikari (Carleton University)

Status of DEAP-3600_IDM_Pushpa.pdf

16:50 The LZ Outer Detector

LUX-ZEPLIN (LZ) is a direct dark matter detection experiment primarily designed to search for WIMPs with a dual-phase Xenon Time Projection Chamber (TPC). It stands at the forefront of dark matter research after obtaining world-leading WIMP-nucleon cross-section constraints with an exposure of 60 days and a fiducial mass of 5.5 t. Located at the Sanford Underground Research Facility (SURF), LZ is currently taking data with the aim of increasing exposure towards a first discovery or improved limits on WIMPs and other dark matter models. The success of LZ is aided by an excellent characterisation of the backgrounds affecting this type of search. Among them, neutron backgrounds are a particularly relevant concern as they can mimic the interaction between WIMPs and nucleons. Fortunately, the LZ Outer Detector (OD) is able to tag these particles with high efficiency, allowing LZ to reach its full potential. The OD consists of 17 t of gadolinium-doped liquid scintillator surrounding the xenon target, viewed by 120 PMTs inside the water tank. The goal of this talk will be to present the OD design, calibration, and performance in past and current LZ science runs.

Speaker: Alberto Usón (University of Edinburgh)

AUson_IDM.pdf

17:10 The XENONnT Neutron Veto: performances without and with Gd-doping.

The Neutron Veto of the XENONnT experiment is a Gd-loaded water Cherenkov detector designed to tag the radiogenic neutrons from the detector materials, in order to reduce the most important Nuclear Recoil backgrounds for the WIMP search in the XENONnT TPC.
The Neutron Veto is instrumented with 120 (8" Hamamatsu R5912) photomultiplier tubes, featuring high-QE and low-radioactivity, installed inside a high light-collection region delimited by ePTFE reflector panels around the cryostat.
In this talk, we describe the Neutron Veto performances in the first XENONnT Science Run, where the Veto has been operated with demineralized water.
We also present the recent operations of Gd-doping of water, and the resulting improved performances.

Speaker: Marco Selvi (Istituto Nazionale di Fisica Nucleare)

XENONnT-nVeto-IDM2024-Selvi.pdf

17:30 The DarkSide-20k experiment

The DarkSide-20k detector is currently under construction at the LNGS laboratory in Italy and is a crucial part of the Global Argon Dark Matter Collaboration’s (GADMC) plan to probe the dark-matter parameter space down and into the neutrino fog. DarkSide-20k is a two-phase Time Projection Chamber with low-radioactivity acrylic walls and optical readout using Silicon Photomultipliers (SiPMs). The inner detector volume is nested in two veto detectors. Notably, DarkSide-20k will be filled with 50 tonnes (20 tonnes fiducial) of Underground Argon, minimizing the cosmogenically-produced background of Ar-39. Unique technical solutions have been developed to ensure excellent sensitivities for direct dark matter searches. We will discuss the design, implemented background reduction techniques, expected sensitivity, and the current status of DarkSide-20k

Speaker: Mr Iftikhar Ahmad (AstroCeNT)

IDM-2024_The_DarkSide-20k_experiment_Iftikhar_Ahmad.pdf

17:50 Low-radiactivity argon for dark matter searches and beyond

The DarkSide-20k experiment seeks to detect dark matter by observing interactions of Weakly Interacting Massive Particles (WIMPs) within a 50-ton target of liquid argon, utilizing double-phase time projection chamber technology. A pivotal element of the experiment is the utilization of low-radioactivity argon depleted in the isotope 39.

The argon's supply chain originates at the Urania plant in Colorado, where low-radioactivity argon is obtained from a CO$_2$ stream sourced from a deep well, at a rate of approximately 250 kg/day. The plant, comprising distillation columns and a pressure swing absorption stage, has already been constructed, with site construction currently underway. Following this initial purification phase, the argon will be transported to Sardinia, Italy, where the Aria plant, featuring a 350 m cryogenic distillation column, will further reduce residual impurities to detector-grade levels. The Aria plant has already been fully constructed and is presently undergoing installation. A smaller-scale version, standing approximately 26 meters tall, has been tested over recent years with highly positive results validating the cryogenic distillation technology.

The significance of this supply chain and the associated techniques extends well beyond DarkSide-20k. Specifically, thirty tonnes of low-radioactivity argon will be supplied to the LEGEND-1000 experiment at LNGS for the veto detector, with an additional tonne earmarked for the COHERNT experiment at ORNL. In a broader perspective, these technologies serve as critical enablers for the ARGO experiment, representing the pinnacle of dark matter search endeavors utilizing argon. Moreover, they have captured the interest of the DUNE collaboration for incorporation into its Module of Opportunity.

Speaker: Riccardo Stefanizzi (Istituto Nazionale di Fisica Nucleare)

IDM_Stefanizzi (1).pdf

IDM_Stefanizzi - Copia.pptx

18:10 Status and short term prospects of DArT, the Underground Ar measurement at Canfranc

DarkSide-20k is under construction at LNGS and is designed to lead the search for heavy WIMPs in the coming years. Measuring the Ar-39 content in underground argon (UAr) is crucial for the successful operation of the detector and, to achieve this goal, the Global Argon Dark Matter Collaboration (GADMC) is building the DArTinArDM experiment at the Canfranc Underground Laboratory in Spain. The DArT chamber, a radiopure detector (~1 liter) filled with UAr, will be situated at the core of the ArDM experiment. With approximately 1 ton of atmospheric argon, ArDM will serve as an active veto against external radiation. DArTinArDM aims to measure the Ar-39 depletion factor in the UAr with a sensitivity greater than 0.1 mBq/kg. This evaluation will be conducted on various samples from each batch of underground argon to ensure their radiopurity meets the necessary standards before filling DS-20k.

In this presentation, I will report on the findings and improvements after 2 years of data taking in a test cryostat and the prospects of the DArTinArDM experiment, which will start operating this year.

Speaker: Vicente Pesudo (CIEMAT)

DArT_IDM_2024-2.pdf

IDM_VPesudo_online

16:30 → 18:50 Parallel 2: Cosmology Dark Matter

Convener: Luigi Pilo (Istituto Nazionale di Fisica Nucleare)

16:30 Cosmology, Big and Small: Probing the Multi-scale Nature of Structure Formation with Artificial Universes

In our present paradigm of galaxy formation, the onset of structure is brought about via the gravitational collapse of dark matter, which subsequently acts as the scaffolding for the visible universe. Decades of numerical simulations have established several features of the dark matter model: the formation of haloes, and how their structure and abundance are influenced by the particle physics of the underlying model. In particular, the nature of the smallest objects in the universe—haloes or galaxies—may be key to unravelling several mysteries underpinning our cosmological model. In this talk, I will review some of the ways in which cosmological simulations can be used to test and predict the phenomenology of dark matter models and will show why the confluence of different probes is necessary to constrain the many ways in which models of dark matter impact structure formation. I will also present some exciting new avenues offered by early universe galaxy formation and gravitational wave astrophysics for testing the dark matter paradigm using future observatories.

Speaker: Sownak Bose (Durham University)

IDM-2024-SownakBose

IDM_2024_Sownak.key

16:50 Mergers of galaxy clusters with velocity-dependent SIDM

Self-interacting dark matter (SIDM) has been proposed to solve small-scale problems in ΛCDM cosmology. Constraints on the self-interaction cross-section of dark matter have been derived assuming that the self-interaction cross-section is independent of velocity. However, a velocity-dependent cross-section is more natural in most theories of SIDM. Using idealized N-body simulations without baryons, we study merging clusters with velocity-dependent SIDM. Simulations have been performed with models that contain either a light mediator(frequent regime) or a heavy mediator(rare regime). The cross-section parameters chosen for simulations respects the most stringent astrophysical constraint on self-interaction cross-section. The results of the simulation will be presented.

Speaker: Sabarish Venkataramani Malathi (University of Hamburg)

IDM.pdf

17:10 The Mochima Simulation: Baryonic physics impact on detailed DM distribution and dynamics on the host halo and subhalos of five realizations of the same Milky-Way-like galaxy.

Cosmological simulations provide a self-consistent framework to study the complex dynamics within galaxies. These simulations are crucial as they examine the interconnected evolution of galactic components. Recent advancements in numerical simulations have significantly enhanced our understanding of baryonic physics—such as stellar processes and interstellar medium dynamics—and their role in shaping galaxies. While the astrophysics community actively investigates the impact of increasingly complex baryonic descriptions on galaxy structures, studies focusing on their effects on dark matter (DM) distributions are less developed. This study utilizes the Mochima simulation, a high-resolution (35 pc) cosmological zoom-in hydrodynamic simulation, which has tested several baryonic models on a Milky Way-like galaxy, resulting in five different galaxy realizations. We examine the DM distribution in these scenarios alongside an additional dark matter-only run. Our analysis highlights changes in halo morphology, geometry, and phase space distributions due to baryonic influences, showing significant variability in mass density profiles and velocity distributions, such as the inner power index varying from 1.3 to 1.8 and broader speed distributions (arXiv:2301.06189). We also explore how the baryonic models affect subhalo distributions, the subhalo mass function, and the impact of baryonic mass on subhalo survival and dynamics in the local DM velocity field. These factors are crucial for dark matter research, especially in direct and indirect detection efforts, making the understanding of baryon-related uncertainties essential. Thus, improving baryonic physics modeling in cosmological simulations is vital not only for understanding galaxy formation but also for enhancing our predictions about dark matter properties and behavior.

Speaker: Arturo Nunez-Castineyra (CEA Saclay, Universite de Paris)

Nunez

Nunez-Castineyra_IDM_LAquila2024.pdf

The Mochima Simulation

17:30 Survival of the prompt cusp population in Milky Way-like galaxies

The current $\Lambda$CDM framework predicts the formation of density cusps in the centre of the first dark matter haloes, which would be able to survive until $z=0$. More specifically, we could find a large number of these prompt cusps with Earth-like masses, which can populate the Milky Way. However, stellar encounters and/or tidal forces might destroy or deplete these structures. In this project, we shed light to the resilience of individual prompt cusps within Milky Way-like galaxies through the Halo Expansion Technique (HEX), which computes the evolution of a subhalo inside the field host halo potential, that resembles a host in a cosmological simulation such as Aquarius (for the DMO case) or Auriga (for the hydrodynamical case). In contrast, the subhalo would be resolved with a large number of particles, and would be orbiting its host for several dynamical times, from its accretion until the present day. We are also able to compare the orbits of these individually simulated subhaloes with their corresponding counterparts in the respective parent simulations, and study the evolution of the density profiles with time. The existence of these prompt cusps at distances close enough to the Earth would be very useful for gamma-ray DM searches, since their annihilation signal would be larger with respect to an NFW subhalo.

Speaker: Alejandra Aguirre-Santaella (Institute for Computational Cosmology, Durham University)

AAS-IDM2024-July8.ppsx

17:50 Dark Sector Tunneling Field Potentials for a Dark Big Bang

All of the significant evidence for dark matter observed thus far has been through its gravitational interactions. After 40 years of direct detection experiments, the parameter space for Weakly Interacting Massive Particles (WIMPs) as dark matter candidates is rapidly approaching the neutrino floor. In this light, we consider a dark sector that is strongly decoupled from the visible sector, interacting exclusively through gravity. In this model, proposed by Freese and Winkler (Phys.Rev.D 107 (2023) 8, 083522) dark matter can be produced through a first-order phase transition in the dark sector dubbed “The Dark Big Bang”. In this study we fully determine the allowed region of parameter space for the tunneling potential that leads to the realization of a Dark Big bang and is consistent with all experimental bounds available.

Speaker: Richard Casey (Colgate University)

Casey_Richard_ IDM24.pptx

16:30 → 18:50 Parallel 3: Axion/Sterile

Convener: Christoph Andreas Ternes (Istituto Nazionale di Fisica Nucleare)

16:30 Status of the Quantum Sensors for the Hidden Sector (QSHS) Experiment

Quantum Sensors for the Hidden Sector is a UK collaboration developing
ultra-low-noise readout and resonant detector technology, aiming
initially to search for halo axions in the 25-40 micro-eV mass window.
The collaboration has continued to develop a range of devices and has
now installed a high-field, low-temperature facility at the University
of Sheffield, centring around a dry dilution refrigerator supplied by
Oxford Instruments having a target physical temperature of 10mK and a
clear bore of 18cm, in which we intend to characterise and test the
ultra-low-noise devices in a haloscope geometry, alongside developing
haloscope and resonant detector technologies. Here, I update on the
QSHS collaboration aims, current progress and characterisation of the
hardware.

Speaker: Mitchell Perry (The University of Sheffield)

IDM-2024_vGiven.pdf

16:47 A new upper limit on the axion-photon coupling with an extended CAST run with a Xe-based Micromegas detector

Solar axion searches with helioscopes have been ongoing for decades, with CAST (CERN axion solar telescope) being the state of the art of this kind of experiment. CAST has been running for more than 20 years. The last solar axion data taking campaign happened during 2019-2021 and is the subject of this talk. The CAST potential was boosted by using the IAXO-pathfinder system, consisting of an ultra-low background Micromegas detector coupled to an X-ray telescope optimized for solar axion searches. This setup provides a high SNR thanks to the optics, which focus the axion signal in a very small area of the readout, and background levels below 2×10$^{-6}$ keV$^{-1}$ cm$^{-2}$ s$^{-1}$ in the energy region of interest. Xe-based gas mixtures have been successfully used for the first time, an important achievement both in terms of higher absorption efficiency and lower background as compared to Ar. The aim of the data analysis is to search for an X-ray excess when pointing towards the Sun, as solar axions are expected to be produced in the Sun via the Primakoff effect. The analysis of the new body of data and its result in the search for solar axions will be presented in this talk.

Speaker: Cristina Margalejo Blasco (Universidad de Zaragoza)

IDM 2024 new CAST limit C. Margalejo.pdf

17:04 Searches of Axion/ALPs with (Baby)IAXO

The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensitivity to the axion-photon coupling $g_{a\gamma}$ down to 10$^{-12}$ GeV$^{-1}$, i.e. 1-1.5 orders of magnitude beyond CAST, the most sensitive axion helioscope to date. The main elements of IAXO are a large superconducting toroidal magnet with eight bores, x-ray focusing optics and low background detectors. An intermediate helioscope on the way to IAXO, called BabyIAXO, with the aim of testing the new technologies for the full scale experiment and also test un-explored region of the axion parameter space, is under construction at DESY. Several components of the experiment are reaching the final stage of development. We will discuss the strategy to perform important tests in the final BabyIAXO location at DESY on different instrumentation and mechanics in preparation to BabyIAXO while waiting for the magnet to be in place. Once completed, BabyIAXO will be able to test gaγ down to 2 $\times$ 10$^{-11}$ GeV$^{-1}$. Already with babyIAXO it will be possible to search for evidence of axion-electron and axion-nucleon coupling in the Sun. Moreover, installing cavities or antennas in the magnet bores will turn BabyIAXO into an axion haloscope, sensitive to dark matter axions in different mass ranges. We will discuss the physics reach of BabyIAXO and present the enhanced sensitivity for axion discovery which will be possible to obtain with the full scale IAXO.

Speaker: Julia Vogel (University of Zaragoza)

IAXO_IDM_July2024_jkvogel.pdf

IAXO_IDM_July2024_jkvogel.pptx

17:21 New results for searches of exotic decays with NA62 in beam-dump mode

The NA62 experiment at CERN took data in 2016–2018 with the main goal of measuring the $K^+ \rightarrow \pi^+ \nu \bar\nu$ decay. In this talk we report on the search for visible decays of exotic mediators from data taken in "beam-dump" mode with the NA62 experiment. NA62 can be run as a ''beam-dump" experiment by removing the kaon production target and moving the upstream collimators into a "closed" position. In this configuration 400GeV protons are dumped on an absorber and New Physics (NP) particles, including dark photons, dark scalars and axion-like particles, may be produced and reach a decay volume beginning 80m downstream of the absorber. More than $10^{17}$ protons on target have been collected in "beam-dump" mode by NA62 in 2021. Recent results from analysis of this data, with a particular emphasis on Dark Photon and Axion-like particle Models, are presented. We also report new results on the first NA62 search for long-lived NP particles decaying in flight to hadronic final states based on a blind analysis of a sample of $1.4 \times 10^{17}$ protons on dump collected in 2021.

Speaker: Jonathan Schubert (CERN)

IDM24_126_NA62Schubert.pdf

17:38 Searches for Physics Beyond the Standard Model at the Short-Baseline Near Detector

The Short-Baseline Near Detector (SBND) is one of three Liquid Argon Time Projection Chamber (LArTPC) neutrino detectors positioned along the axis of the Booster Neutrino Beam (BNB) at Fermilab, as part of the Short-Baseline Neutrino (SBN) Program. The detector is currently being commissioned and is expected to take neutrino data this year. SBND is characterized by superb imaging capabilities and will record over a million neutrino interactions per year. Thanks to its unique combination of measurement resolution and statistics, SBND will carry out novel searches for physics beyond the Standard Model (BSM). As the near detector, it will enable the potential of the overall SBN sterile neutrino program, and be sensitive to any new BSM particles produced in the beam such as heavy neutral leptons, dark photons, heavy axions, dark neutrinos, and millicharged particles. In this talk, the physics reach, current status, and future prospects of SBND are discussed.

Speaker: Xiao Luo (UCSB)

BSM_SBND.pdf

17:55 Searching for Dark Sector Particles in the NEON Experiment at a Reactor Facility

The NEON (Neutrino Elastic-scattering Observation with NaI) experiment at the Hanbit nuclear power plant in Yeonggwang uses an array of NaI(Tl) crystals to search coherent elastic neutrino-nucleus scattering (CEvNS) with reactor anti-electron neutrinos. The experiment features a 16.7 kg NaI(Tl) target mass situated 23.7 meters from the reactor core and has collected physics data over a 24-month period. Beyond CEvNS, NEON is designed to investigate dark sector particles that are emitted by high-energy photons (MeV scale) from the reactor core. This includes searches for dark photons and axion-like particles (ALPs), both theorized to be in the similar MeV or lower mass range. In this presentation, I will discuss our recent efforts and findings in searching for these dark sector particles through the NEON experiment.

Speaker: Seo Hyun Lee

2024IDM_NEON_SHLee.pdf

18:12 keV sterile neutrinos search with the KATRIN experiment

The KATRIN experiment is designed to measure the mass of the electron anti-neutrino by studying the high energy end of the tritium β decay spectrum. In addition, KATRIN is also a well suited instrument to explore the sterile neutrino hypothesis. The existence of sterile neutrinos would cause a kink-like distortion in the spectrum.

Using the same datasets as for active neutrino mass, KATRIN has previously presented results on the search for sterile neutrinos at the eV scale, complementing the reactor and radioactive source experiments. With an endpoint of 18.6 keV, KATRIN also offers a high potential for the search of sterile neutrinos in the keV range. With data acquired during the 2018 commissioning campaign, KATRIN reported results from a search for keV-scale neutrinos in the restricted mass range of 0.01 to 1.6 keV. No keV-sterile neutrino signal was observed and KATRIN reported exclusion limits competitive with other laboratory-based searches. The current KATRIN detector is not designed to handle the higher count rate that occurs with a wider mass range. Equipped with the TRISTAN detector KATRIN aims to search for keV sterile neutrinos across the full tritium beta decay spectrum. This detector is currently in production and is scheduled to be operational in KATRIN in 2026.

In this talk, I will present the latest results from KATRIN on the search for keV sterile neutrinos, as well as the ongoing efforts to conduct a high sensitive search with the TRISTAN detector.

Speaker: Anthony Onillon (TUM)

IDM2024_keVsterile_ONILLON.pdf

19:00 → 21:00 Welcome Party

Tuesday, 9 July

09:00 → 10:30 Plenary

Convener: Karl Van Bibber

09:00 Illuminating the Dark Universe with Euclid

Euclid is a space mission aimed at addressing the key questions of modern cosmology. After a long process started in 2007 in the framework of the ESA Cosmic Vision 2015-2025, it was successfully launched in 2023. Euclid will shed light on the nature of dark energy, the properties of dark matter and its relations with baryonic matter, the mass of neutrino and will test modified gravity on cosmological scales. The revolutionary power of Euclid relies on the combination of different, independent and complementary probes: weak gravitational lensing, baryonic acoustic oscillations, redshift-space distortions, galaxy clusters, strong lensing and cross-correlations with the cosmic microwave background. To achieve these ambitious goals, Euclid will observe about 1/3 of the sky (about 15,000 square degrees) with visible and near-infrared imaging, plus near-infrared spectroscopy, in order to collect data of huge volumes of the universe at different cosmic epochs spanning the last 10 billion years. Euclid data will include high-quality images and photometric redshifts for more than 2 billion galaxies, as well as spectroscopic redshifts and spectra for tens of million galaxies. The legacy value of the Euclid dataset will be immense also for a wide range of other science cases in astrophysics and cosmology. The presentation will illustrate Euclid in general and will focus on its role to constrain the properties of dark matter.

Speaker: Andrea Cimatti (University of Bologna)

Cimatti_IDM24_09lug24.pdf

09:30 Theoretical framework for Dark Matter Axions

The QCD axion offers a compelling solution to the strong CP problem and a well-motivated dark matter candidate, inspiring several ultra-sensitive experiments probing light and weakly-coupled dark sectors. After reviewing the theoretical framework for dark matter axions, I will focus on recent developments in axion model building suggesting that the QCD axion parameter space is much larger than what traditionally thought. Implications for present and future axion detection experiments will be discussed as well.

Speaker: Luca Di Luzio (Istituto Nazionale di Fisica Nucleare)

Di Luzio_IDM2024.pdf

10:00 Experimental search of Dark Matter Axions

This talk will review the experimental landscape of axion and axion-like particle searches and introduce the various types of setups employed to look for the elusive particle initially proposed to solve the strong CP problem.

Speaker: Julia Vogel (University of Zaragoza)

Axion_experiments_IDM_July2024_vogel_finalv.pdf

10:30 → 11:00 Coffee break

11:00 → 12:30 Plenary

Convener: Luca Visinelli (Stockholm University &amp; Nordita)

11:00 Axion constraints from astrophysical observations

Axions and axion-like particles are promising particle candidates to explain cold dark matter. These particles could be detected through their feeble interaction with photons, which could lead to observable signatures in a variety of astrophysical observations. On the one hand, photons and axions produced in astrophysical sources could oscillate into each other in astrophysical magnetic fields leading to distinct features in the sources’ multiwavelength spectra. Similarly, dark matter axions could convert into photons in strong magnetic fields of pulsars. On the other hand, dark matter axions with masses around the eV scale could decay into two photons at infrared wavelengths. In this talk, I will review recent advancements in these astrophysical axion searches.

Speaker: Manuel Meyer (University of Southern Denmark)

Meyer_Axion_Astro_IDM2024.key

Meyer_Axion_Astro_IDM2024.pdf

11:30 Primordial black holes or else?

Detecting a primordial black hole (PBH) would be an outstanding discovery with strong implications on cosmology, high-energy physics, and astrophysics. I will overview recent results about: I) individual-event searches for PBHs with gravitational-wave detectors; II) quantifying the evidence for PBHs in current data and with future detectors Einstein Telescope and LISA, using population studies. I will systematically discuss a comprehensive and interconnected list of discriminators that would allow us to rule out, or potentially claim, the primordial (vs astrophysical) origin of a binary (or population thereof) by measuring different parameters, including redshift, masses, spins, eccentricity, and tidal deformability.

Speaker: Paolo Pani (Sapienza University of Rome)

PBHs_Aquila_IDM_2024.pdf

12:00 Dark stars

There are strong indications that dark matter might exhibit self-interactions. In the case of asymmetric dark matter, such interactions might lead under certain conditions to the collapse of dark matter and the formation of compact objects. These dark stars can be probed in various ways. Firstly they have a different gravitational waveform from black holes and neutron stars in merger events. Secondly, they can produce photon outbursts due to trapped protons and electrons in their core. Dark stars can also affect the 21 cm radiation.

Speaker: Christoforos Kouvaris

Kouvaris_IDM2024.pdf

12:30 → 14:00 Lunch

14:00 → 16:00 Parallel 1: Direct detection

Convener: Aldo Ianni (Istituto Nazionale di Fisica Nucleare)

14:00 Annual modulation results from DAMA/LIBRA

The DAMA/LIBRA experiment (about 250 kg of highly radio-pure NaI(Tl)), is running deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N.; its main aim is the investigation of Dark Matter (DM) particles in the Galactic halo by pursuing the model independent DM annual modulation signature. The results released so far have been obtained with the data of the first phase of measurements (DAMA/LIBRA-phase1) lasted for seven annual cycles with an exposure of 1.04 ton x yr and the data of the second phase (DAMA/LIBRA-phase2), with lower software energy threshold of 1 keV. The DAMA/LIBRA—phase2 has released so far data corresponding to 8 annual cycles for a cumulative exposure of 1.53 ton x yr. DAMA/LIBRA data (and those of the former DAMA/NaI set-up) give evidence for the presence of DM particles in the galactic halo with 13.7s C.L. in the energy region below 6 keV. No systematic or side reaction able to mimic the exploited DM signature has been found. The obtained DAMA model independent result is compatible with a wide set of scenarios regarding the nature of the DM candidate and of the related
astrophysical, nuclear and particle physics models. The experiment has been further upgraded in October 2021 when new pre-amplifiers with HV divider system, and new Transient Digitizers have been installed. This last phase of measurement is ongoing. In this talk, a summary of the results obtained so far by DAMA/LIBRA will be presented and the perspectives of the present new presently running configuration will be discussed.

Speaker: Riccardo Cerulli (Istituto Nazionale di Fisica Nucleare)

Cerulli_IDM2024.pdf

14:20 Status and prospects of the SABRE North experiment and NaI(Tl) crystal radiopurity

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 reliant on a joint crystal R&D activity, located in the Northern (LNGS) and Southern hemispheres (SUPL). For over 10 years, SABRE has conducted extensive R&D on ultra-radio-pure NaI(Tl) crystals. Several crystals have been grown and tested in both active and passive shields at LNGS. Based on these results, SABRE North is proceeding with a full-scale design incorporating purely passive shielding. To achieve an unprecedented level of radiopurity for NaI(Tl) crystals, SABRE North is employing zone refining purification of the NaI powder prior to growth. We will present the first results from the zone refining activities and predictions on the ultimate radio purity achievable for the crystals. Additionally, the status of the SABRE North installation at LNGS will be discussed.

Speaker: Davide D'Angelo

slides_IDM2024_SABRE.pdf

14:40 ANAIS-112: the most sensitive experiment to test the DAMA/LIBRA signal in a model independent way

The ANAIS (Annual modulation with NaI(Tl) Scintillators) experiment is intended to search for dark matter annual modulation with ultrapure NaI(Tl) scintillators in order to provide a model independent confirmation or refutation of the long-standing DAMA/LIBRA positive annual modulation signal in the low energy detection rate, using the same target and technique. Other experiments exclude the region of parameters singled out by DAMA/LIBRA. However, these experiments use different target materials, so the comparison of their results depends on the models assumed for the dark matter particle and its velocity distribution in the galactic halo. ANAIS-112, consisting of nine 12.5 kg NaI(Tl) modules produced by Alpha Spectra Inc., disposed in a 3×3 matrix configuration, is taking data smoothly with excellent performance at the Canfranc Underground Laboratory, Spain, since August, 2017. Last results corresponding to the reanalysis of the first 3 years data using new filtering protocols based on machine-learning techniques lead international efforts in testing the DAMA/LIBRA signal, and are compatible with the absence of modulation and incompatible with DAMA/LIBRA for a sensitivity of almost 3σ C.L., with the potential to reach a 5σ level by the end of 2025. These results will be reported in this talk. The scintillation quenching factors constitute the main systematics in the comparison between the DAMA/LIBRA result and other experiments using NaI(Tl). The impact of different scintillation quenching factors in the comparison between ANAIS-112 and DAMA/LIBRA will also be addressed. Finally, the present status of the experiment and prospects for the upcoming 6-years unblinding will be discussed.

Speaker: Iván Coarasa Casas (CAPA, Universidad de Zaragoza)

IDM2024_ANAIS112_IvanCoarasa_vdef.pdf

15:00 Dark Matter Annual Modulation Search in COSINE-100 Full Dataset and Beyond

The event rate from dark matter interactions is expected to exhibit annual modulation due to their halo-shaped galactic distribution. However, this signature has only been conclusively observed in the reports by DAMA, which utilized NaI(Tl) scintillators. Although their claim could be interpreted as dark matter scattering, other experiments have yet to replicate it using different scintillation materials. To address this puzzle, the COSINE-100 experiment, employing 106 kg of the same material, NaI(Tl), was established as a direct and model-independent test of the DAMA result. Operating from September 2016 to March 2023 at the Y2L underground laboratory in South Korea, COSINE-100 collected optimal data for testing DAMA's findings. This presentation will share recent results from the annual modulation analysis of the COSINE-100 full dataset.
Various additional physics searches have also been conducted, and these findings will be discussed. COSINE-100 completed its initial mission phase last year and is now undergoing upgrades to become COSINE-100U. At its new, deeper home in Yemilab, it will continue the dark matter search campaign with enhanced encapsulation techniques. The talk will provide the status and prospects of the upgrade program, along with plans for the next-generation experiment, COSINE-200.

Speaker: SeungMok Lee (Seoul National University)

240709_COSINE100ModulationFullDatatset.pdf

15:20 A combined search for dark matter with COSINE-100 and ANAIS-112

The evidence for the existence of dark matter from astrophysical observations is strong. However, there has not been a conclusive direct detection of dark matter that does not rely on gravitational interaction with visible matter. One experiment, DAMA, claims to have observed an annual modulation signal in a sodium-iodide-based detector consistent with that expected from dark matter. COSINE-100 and ANAIS-112, two leading sodium-iodide dark matter experiments, were designed to test DAMA’s claim directly using the same target material. COSINE-100, located at Yangyang Underground Laboratory in South Korea, and ANAIS-112, located at Canfranc Underground Laboratory, have been taking data since 2016 and 2017, respectively. The two experiments have similar sensitivity and have thus far published results independently. In this talk, I will discuss our efforts to combine the data from the two experiments for increased search sensitivity and share its current status.

Speaker: Sophia Hollick (Yale University)

combined_COSINE_ANAIS.pdf

15:40 The COSINUS dark matter search experiment

Today, direct dark matter detection results are contradicting: the DAMA/LIBRA experiment observes an annual modulation signal at high confidence. Furthermore, this signal is perfectly compatible in terms of period and phase with the expectation for a galactic halo of dark matter particles interacting in their NaI target crystals. However, in the so-called standard scenario on dark matter halo and dark matter interaction properties, the DAMA/LIBRA signal contradicts the null results of numerous other experiments.

The new experiment COSINUS aims for a model-independent cross-check of the DAMA/LIBRA signal. Such a cross-check has been absent for now and necessarily requires using the same target material (NaI). COSINUS is the only NaI -based experiment operating NaI as a cryogenic detector, which yields several distinctive advantages: discrimination between electronic interactions and nuclear recoils off sodium and iodine on an event-by-event basis, a lower nuclear recoil energy threshold, and a better energy resolution. We finished the construction of the COSINUS experiment at LNGS in 2023; the cryostat is already running at base temperature. In this contribution, we will report on the prototype demonstrator measurement and give an outlook on the last steps towards the start of the data taking.

Speaker: Florian Reindl (HEPHY and TU Vienna)

IDM2024_COSINUS_Reindl_v3.pdf

14:00 → 16:00 Parallel 2: Theory

Convener: Fabrizio Nesti (Istituto Nazionale di Fisica Nucleare)

14:00 MOND: An alternative to particle dark matter

Milgromian dynamics (MOND) is a major alternative to non-baryonic particle dark matter, proposed by Moti Milgrom in 1983. In this invited talk, I will review the multiple successful predictions that MOND had on galaxy scales, as well as the long-standing challenges it faces on galaxy-cluster and cosmological scales. In particular, I will describe the dynamical regularities and empirical laws followed by rotating galaxies, which point to the existence of a characteristic acceleration scale in the dark matter problem. I will also discuss recent progress in building relativistic extensions of MOND, which allow reproducing the cosmic microwave background, the linear matter power spectrum, and the correct propagation speed of gravitational waves.

Speaker: Federico Lelli (INAF - Arcetri Astrophysical Observatory)

Lelli_Aquila.pdf

14:20 Galactic Dark Matter from General Relativity

If the dynamics of a disc galaxy is analysed from a general-relativistic viewpoint (GR), it turns out in general that the solution cannot be approximated by Newtonian theory, as is usually believed. Even under the simplifying assumptions of stationarity, axisymmetry and zero pressure (i.e. the velocity dispersion is neglected), non-Newtonian features can arise, which are ascribed to the essential role of the frame dragging. Such a “strong dragging" may contribute to sustain the observed galaxy rotation curves. Rotation curves constitute one of the main indirect measurement techniques for galactic mass. If taken into account, dragging can therefore lead to a re-weighting of the mass of galaxies, and hence of the galactic dark matter.
Future experiments to find dark matter could thus be improved. We also propose various techniques to empirically observe the possible presence of the strong dragging, in our Galaxy or in some distant ones.

Speaker: Federico Re (Milano Bicocca)

GR&DM.pdf

GR&DM.pptx

14:40 Unified model for particles and condensate Dark Matter: The role of self-interaction

We present from first principles, under the Schwinger-Keldysh path integral formalism, equations for bosonic, non-relativistic and self-interacting dark matter which can include both a condensed, low momentum “fuzzy” component and one with higher momenta that may be approximated as a collection of particles. The equations can describe both CDM and Fuzzy Dark Matter in a unified way and it can reduce to the limit of known equations in cold atom physics in absence of gravity. We show that self-interaction plays an important role in the growth of the condensate and initial generation with the presence of stochastic noise terms.
We also present the linear regime of this mixed model and we show how the existence of these two components and the interaction between the condensate and particles can bypass Lyman alpha forest bounds for Fuzzy Dark Matter.

Speaker: Alex Soto (Newcastle University)

ASoto-laquila.pdf

15:00 Axion-like particles as probes of the SN core

Pseudo-scalar particles, like QCD axions and Axion-like-Particles (ALPs), emerge in many extension of the Standard Model and have been recognized to be among the best Dark Matter candidates. Even if very weakly interacting, ALPs can be copiously in the core of massive stars at the end of their life. In this regard, Core-Collapse Supernovae (SNe) are expected to be powerful sources of novel exotic particles. Thus, a future Galactic SN may represent a
once-in-a-lifetime opportunity for the detection of such Dark Matter candidate. In this talk, I will discuss how ALPs with masses $m_a<10^{-10}$ eV may be efficiently produced in SN cores by means of their coupling to nucleons. Then, they can leave the star unimpeded and convert into photons inside galactic magnetic fields, giving rise to an ALP-induced $\gamma$-ray burst at energies $E\gtrsim 50\,\mathrm{MeV}$, which might be detectable in the Fermi-LAT experiment.
Moreover, since ALP production mechanisms are sensitive to the conditions of the inner regions of the SN core, I will argue how ALPs can be employed to probe some important properties of Proto-Neutron Stars (PNS). In particular, I will show that the detection of the ALP burst may provide some insights about the presence of a relevant fraction of pions in SN cores and, eventually, lead to the reconstruction of the temperature in the inner region of the PNS.

Speaker: Alessandro Lella (Istituto Nazionale di Fisica Nucleare)

2024_IDM2024_Lella_forPDF.pdf

15:20 Searching for a DM candidate via antiprotonic 3He

A wide range of dark matter candidates have been proposed and are actively being searched for in a large number of experiments, both at high (TeV) and low (sub meV) energies. One dark matter candidate, a deeply bound uuddss sexaquark, S , with mass $\sim$ 2 GeV,
(having the same quark content as the hypothesized H-dibaryon, but long lived) is particularly difficult to explore experimentally. Here, we propose a scheme in which such a state could be produced at rest through the formation of $\bar{p}^3$He antiprotonic atoms and their annihilation into K$^+$K$^+$$\pi^-$ , identified both through the unique tag of a S=+2, Q=+1 final state, as well as through full kinematic reconstruction of the final state recoiling against it.

Speaker: Michael Doser (CERN)

MDoser_Searching_for_a_DM_candidate_via_antiprotonic_3He.pdf

15:40 Warm Surprises from Cold Duets: N-Body Simulations with Two-Component Dark Matter

We explore extensive N-body simulations with two-component cold dark-matter candidates. We delve into the temperature evolution, power spectrum, density perturbation, and maximum circular velocity functions. We find that the substantial mass difference between the two species and the annihilation of the heavier components to the lighter ones effectively endow the latter with warm dark-matter-like behavior, taking advantage of all distinct features that warm dark-matter candidates offer, without observational bounds on the warm dark-matter mass. Moreover, we demonstrate that the two-component dark-matter model aligns well with observational data, providing valuable insights into where and how to search for the elusive dark-matter candidates in terrestrial experiments.

Speaker: Jong-Chul Park (Chungnam National University)

2CDM_WDM-like_JCPark.pdf

14:00 → 16:00 Parallel 3: Light Dark Matter

Convener: Carla Macolino (Istituto Nazionale di Fisica Nucleare)

14:00 Commissioning of the MIGDAL detector with fast neutrons at NILE/ISIS

Direct dark matter search experiments increasingly rely on the Migdal effect, a rare atomic process, to enhance sensitivity to low-mass WIMP-like candidates. Despite its theoretical prediction in the late 1930s and subsequent observation in radioactive decays, the Migdal effect remains unobserved in nuclear scattering. The MIGDAL experiment aims to achieve the first unambiguous measurement of this phenomenon. We employ a low-pressure optical Time Projection Chamber filled with low-pressure gas to observe nuclear recoils induced by an intense DD neutron generator. Our choice of gas is CF4, for its avalanche-quenching properties and scintillation in the visible spectrum; the latter of which allows for the tracks to be imaged in high-resolution by a fast, low-noise camera. This is then combined with timing information from an independent ionisation readout to achieve 3D-track reconstruction.

Commissioning data has been collected using fast neutrons at the Neutron Irradiation Laboratory for Electronics (NILE) at Rutherford Appleton Laboratory in the UK. This talk shares the commissioning results, highlighting the detector’s performance with a high rate of highly ionising nuclear recoils. Additionally, we will discuss the detector’s capability to operate across a wide dynamic range, crucial for imaging the characteristic Migdal topology.

Speaker: Tim Marley (Imperial College London)

IDM_2024_MIGDAL_Tim_Marley.pptx

MIGDAL_IDM_2024

14:20 MIRACLUE: Migdal effect search using position sensitive gaseous detectors

The Migdal effect associated with nuclear scattering is very important in the dark matter search. In order to experimentally verify the Migdal effect, we are searching for Migdal effect by using poistion sensitive gaseous detectors. We have two types of detector as followings: Ar detector with u-PIC readout and Xe detector with electroluminescence readout. As for the Ar detector result, we will report on the status of the latest neutron beam test, and regarding Xe detector, we will report on the analysis result of the first trial neutron beam test.

Speaker: Kiseki Nakamura (Tohoku university)

kisekinakamura_IDM_miraclue.pdf

14:40 Light Dark Matter in Direct Detection: Plasmon and Migdal Effects

The WIMP hypothesis has been a leading contender, yet recent null results from WIMP searches have prompted extensive exploration of alternative possibilities, particularly focusing on sub-GeV dark matter. Given that the nuclear recoil of light dark matter falls below the threshold of conventional detectors, great efforts have focused on utilizing ionization signals to extend sensitivity in direct detection experiments. In this talk, I will talk about two new important ionization signals from plasmon resonance in DM-electron scatting in semiconductors and Migdal effects in DM-nucleus scattering in noble liquid detectors. We found these novel mechanism can be used to extend the sensitivity of searching for light dark matter in conventional direct detections.

Speaker: Lei Wu (Nanjing Normal University)

2024 ITALY-Sub-GeV and Ionization.pptx

15:00 Improved modeling of charge trapping and impact ionization in phonon-based crystal detectors used for dark matter searches

Various dark matter search experiments employ phonon-based crystal detectors operated at cryogenic temperatures. Some of these detectors, including HVeV detectors used by the SuperCDMS collaboration, are able to achieve single-charge sensitivity when a voltage bias is applied across the detector. The total amount of phonon energy measured by such a detector is proportional to the number of electron-hole pairs created by an interaction. However, crystal imperfections and surface effects can cause propagating charges to either trap inside the crystal or ionize additional charges, producing non-quantized measured energy as a result. Modeling these detector-response effects continues to be important for understanding and distinguishing between different sources of events, as well as for modeling the detector response of potential signals for dark matter searches. This presentation showcases an improved, more robust model of these detector-response effects that has fewer limitations and is capable of modeling more effects compared to previous models. This model allows for more accurate characterization of phonon-based crystal detectors and may facilitate discrimination between potential dark matter signals and background sources.

Speaker: Matthew Wilson

IDM_2024_mwilson_v2.pdf

15:20 Theoretical upper bounds on the dark matter-electron scattering rate in the generalised susceptibility formalism

Direct-detection experiments seek signals generated by dark matter particles interacting with the microscopic constituents of detector materials.

In our work, we combine a non-relativistic effective theory for DM-electron interactions with the linear response theory to describe the scattering of sub-GeV DM particles in Si, Ge, Xe and Ar detectors.

Within this formalism, the detector response to an arbitrary DM-electron interaction is described in terms of generalised susceptibilities, which extend the notion of dielectric function to general DM-detector couplings.

It can be shown that due to the requirement of analyticity and causality, some of those generalised susceptibilities, and thus the associated scattering rates, are bounded from above.

We compare the expected scattering rates in currently used detector materials with our predicted theoretical upper bound and explore the properties an optimal material should have in order to saturate this bound and thus maximize the possible detector response.

Speaker: Michał Iglicki (Chalmers University of Technology)

iglicki_idm2024.pdf

15:40 Optimal anti-ferromagnets for light dark matter detection

We argue that anti-ferromagnets (in particular, nickel oxide) are optimal targets to look for sub-MeV dark matter with spin-dependent interactions. We show how they can potentially be sensitive to dark matter as like as the keV, with nickel oxide performing an order of magnitude better than all other compounds.
We also show how a powerful theoretical tool to approach this problem is that of effective field theories for spontaneously broken spacetime symmetries.

Speaker: Angelo Esposito (Università Roma La Sapienza)

IDM Esposito.pdf

16:00 → 16:30 Coffee break

16:30 → 18:50 Parallel 1: Direct detection

Convener: Carla Macolino (Istituto Nazionale di Fisica Nucleare)

16:30 The SABRE South Experiment at the Stawell Underground Physics Laboratory

The SABRE experiment aims to detect an annual rate modulation from dark matter interactions in ultra-high purity NaI(Tl) crystals in order to provide a model independent test of the signal observed by DAMA/LIBRA. It is made up of two separate detectors that rely on joint crystal R&D activity; SABRE South located at the Stawell Underground Physics Laboratory (SUPL), in regional Victoria, Australia, and SABRE North at the Laboratori Nazionali del Gran Sasso (LNGS).

SABRE South is designed to disentangle seasonal or site-related effects from the dark matter-like modulated signal by using an active veto and muon detection system. Ultra-high purity NaI(Tl) crystals are immersed in a Linear Alkyl Benzene (LAB) based liquid scintillator veto, further surrounded by passive steel and polyethylene shielding and a plastic scintillator muon veto. Significant work has been undertaken to understand and mitigate the background processes, taking into account radiation from the detector materials, from both intrinsic and cosmogenic activated processes, and to understand the performance of both the crystal and veto systems.

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.
The commissioning of SABRE South started in early 2024 and the first equipment including the muon detectors have been already installed in SUPL.

This talk will report on the general status of the SABRE South assembly, its expected performance, and the design of SUPL.

Speaker: Elisabetta Barberio

sabre_South_IDM24_vf.pdf

16:50 Measurements of low energy nuclear recoil quenching factors for NaI(Tl) scintillating crystal

Understanding nuclear recoil quenching factors, the ratio of the scintillation light yield produced by nuclear and electron recoils of the same energy, is critical for rare event searches, such as dark matter and neutrino experiments. Because NaI(Tl) crystals are widely used for dark matter direct detection and neutrino-nucleus elastic scattering measurements, the low-energy quenching factor of the NaI(Tl) crystals is substantially important. The quenching factor for NaI(Tl) scintillating crystals has been measured by several experimental groups for energies above 5 keVnr for Sodium and 10 keVnr for Iodine. We have developed a NaI(Tl) detector with a high light yield of approximately 25 photoelectrons per keVee and an event-selection and analysis method based on waveform simulations that are specialized for studies of events with energies as low as a sub keVee region. As part of these efforts, we have measured quenching factors for nuclear recoil energies below 5 keVnr and 10 keVnr for Na and I, respectively. Furthermore, a reevaluation of previously reported QF results is conducted, incorporating enhancements in low energy events based on waveform simulation. The outcomes are generally consistent with various recent QF measurements for sodium and iodine.

Speaker: Seo Hyun Lee

2024IDM_QF_SHLee.pdf

17:10 Dark matter search opportunities with NaI scintillating crystals using SiPMs at cryogenic temperatures

Although there exist multiple and strong evidences of the presence of dark matter in our universe, its nature is still unknown. Only one experiment, DAMA/LIBRA, has provided a hint on the detection of the galactic dark matter by observing an annual modulation in the detection rate. Although this signal is very difficult to reconcile with the negative results from other experiments, it is also impossible to provide a model-independent confirmation or refutation using different target nuclei. This is the goal of several experiments using NaI as target material, either in data taking phase, as ANAIS-112 at the Canfranc Underground Laboratory, or under R&D.

Among the latter, this talk will focus on the ANAIS+ project. The goal is moving forward in sensitivity with respect to ANAIS-112 by reducing the energy threshold significantly while improving the radiopurity of the crystals and the background rejection strategy. This increase in sensitivity of the technique will make ANAIS+ competitive in the searches for light mass WIMPs with spin-dependent interactions, but also for the study of neutrino-nucleus coherent scattering, for instance. In addition, it would enable testing the DAMA/LIBRA signal overcoming the uncertainties introduced by the poor knowledge of the scintillation quenching factors for sodium and iodine recoils.

The ANAIS+ experimental approach relies on the replacement of the PMTs by SiPMs and the operation at low temperature. This approach takes advantage of the high quantum efficiency of SiPMs, the highly suppressed dark noise and the increased light yield of pure NaI at low temperatures, which will enable a significantly reduced energy threshold. Furthermore, avoiding spurious light produced in the PMTs will help to increase the efficiency of the event selection procedures and the possibility of operation inside a LAr bath will enable vetoing dangerous background contributions in the region of interest. ANAIS+ is a collaborative effort between LNGS, CIEMAT and University of Zaragoza. The status of the ANAIS+ project, first tests ongoing and prospects will be presented in this talk.

Speaker: Jaime Apilluelo Allué (CAPA - University of Zaragoza)

IDM2024_ANAIS+.pdf

17:30 ASTAROTH, an innovative detector for dark matter direct detection experiments

In the long standing search for dark matter’s annual modulation with NaI(Tl) detectors, all current generation experiments are plagued with noise from the PMTs which is about an order of magnitude higher than the signal at the keV recoil energies of interest.
ASTAROTH is an R&D project aiming to replace PMTs with SiPM matrices in order to highly enhance the signal-to-noise in the region of interest and lower the detection threshold bew 1 keV where potentially a large fraction of signal awaits undetected.
SiPMs offer several advantages in terms of efficiency of light conversion, radiopurity, compactness  and especially noise, if operated at cryogenic temperatures.
ASTAROTH has developed a cryostat where the 5-cm cubic crystals can be cooled gently in He atmosphere while the cooling power is provide by a liquid argon bath that could be instrumented and act as a veto detector.
The design is innovative as a tunable temperature con be kept constant in the inner copper chamber in the range 87-150 K allowing to find the optimal working point accounting for the crystal response and the SiPM noise. The cryostat was commissioned and operated successfully in 2023.
We are also developing a new technique to encapsulate crystals in epoxy resins in order to maintain the transparency on all sides and allow for safe manipulation through the cooling cycles. Early results
are encouraging and could be a breakthrough for NaI users.
Finally, we are comparing the performance of large area SiPM matrices from different vendors and developing different front-end electronics based on discrete and integrated technologies with the ambition of providing a working solution that goes beyond our physics scope and could replace PMTs for low energy astroparticle applications in a wide community.

Speaker: Valerio Toso (Istituto Nazionale di Fisica Nucleare)

PresentazioneIDM.pdf

17:50 Opportunities at the Sanford Underground Research Facility

The Sanford Underground Research Facility (SURF) has been operating for 17 years as an international facility dedicated to advancing compelling multidisciplinary underground scientific research in rare-process physics, as well as offering research opportunities in other disciplines. SURF laboratory facilities include a Surface Campus as well as campuses at the 4850-foot level (1490 m, 4300 m.w.e.) that host a range of significant physics experiments, including the LUX-ZEPLIN (LZ) dark matter experiment and the MAJORANA DEMONSTRATOR rare-decay experiment. As some experiment activities are completing, a call has been issued for letters of interest for Davis Campus space. The CASPAR nuclear astrophysics accelerator completed the first phase of operation at the Ross Campus and is planning for the second phase beginning in 2024. SURF is also home to the Long-Baseline Neutrino Facility (LBNF) that will host the international Deep Underground Neutrino Experiment (DUNE). SURF offers world-class service, including an ultra-low background environment, low-background assay capabilities, and electroformed copper is produced at the facility. SURF is preparing to increase underground laboratory space. The initial phase of construction is underway for new large caverns (nominally 100m L x 20m W x 24m H) on the 4850L (1485 m, 4100 m.w.e.) on the timeframe of next-generation dark matter and neutrino experiments (~2030).

Speaker: Jaret Heise (SURF)

Heise - SURF IDM-2024_07_09.pdf

18:10 Boulby Underground Laboratory: Status update and future plans

At 1100m beneath the earth on the north-east coast of England, the STFC Boulby Underground Laboratory has been involved in the search for dark matter for the past 30 years. However, this only scratches the surface of the science that has been performed at Boulby. Multidisciplinary projects at Boulby include particle and astroparticle physics, geology and geophysics, climate studies, environmental studies and the study of life in extreme environments. The Boulby Underground Laboratory also plays host to the Boulby Underground Screening (BUGS) facility which employs a range of sensitive techniques to characterise the radioactivity of candidate materials for low-background particle physics experiments.

With STFC, We are now planning for a major expansion of our facilities over the next 10 years with the aim of hosting a large scale next-generation astroparticle physics project as well as consolidating and expanding on our multi-disciplinary science programme.

This talk will give details of the current facility and science programme and the future expansion.

Speaker: Paul Scovell (STFC)

20240709_iDM_Scovell.pdf

18:30 Seeking Dark Matter in the Southern Hemisphere with PAUL

The Paarl Africa Underground Laboratory (PAUL) feasibility study has been launched in 2024. It will be the first dedicated and permanent underground laboratory in Africa, and only the second one in the southern hemisphere. Under 800 metres of rock forming the Du Toitskloof mountain in the western Cape region, it would not be the world’s deepest or biggest underground lab, but would offer physics researchers in southern Africa the chance to participate in the global search for dark matter. At high dark matter masses, only detectors using noble liquids can reach the required sensitivity. This implies larger volumes and, as a consequence, wide footprints to host all subsystems. While the underground site for those experiments is not yet defined, a novel underground site that does not surpass the existing ones in terms of depth can hardly be a good choice for them. At small dark matter masses, however, there are many new opportunities to which a novel underground laboratory can contribute. One of the most interesting facts about having the possibility to perform an experiment of direct dark matter detection in an underground laboratory located in the Southern Hemisphere is to compare the modulation with respect to the same detector in the Northern Hemisphere. The strong synergy between the astrophysical (indirect) probes and Paarl Africa Underground Laboratory (direct probe) can jointly measure and constrain dark matter effect, which may shed lights on new physics. A progress report and the prospects of the initiative will be presented.

Speaker: Marcello Messina (Istituto Nazionale di Fisica Nucleare)

PAUL_IDM24_2.pptx

16:30 → 18:50 Parallel 2: Theory

Convener: Nicola Rossi (Istituto Nazionale di Fisica Nucleare)

16:30 Strongly interacting dark sectors with light vector mesons

The dark pion, $\pi_{D}$, is generally the lightest meson of strongly interacting dark sectors, which makes it a popular dark matter candidate. However, it is facing the challenge of simultaneously reproducing the relic abundance and satisfying constraints on dark matter self-interaction from the Bullet Cluster. This challenge can be overcome by considering additional light mesons of the dark sector, such as the vector meson $\rho_{D}$. In such a set-up, the $3\pi_{D}\rightarrow\pi_{D}\rho_{D}$ annihilation channel dominates the freezeout of the $\pi_{D}$, allowing higher $\pi_{D}$ masses and weaker self-interactions. Additionally, the $\rho_{D}$ is forced to decay into standard model states, revealing the possibility of exciting novel signatures, such as displaced vertices and emerging and semi-visible jets.

Speaker: Nicoline Hemme (Karlsruher Institut für Technologie)

IDM2024_Hemme.pdf

16:50 Dark Particles at the LHC: LHC-Friendly Dark Matter Characterization via Non-Linear EFT

Conventional methods for elucidating the behavior of Dark Matter (DM), such as effective field theory (EFT) and simplified models, have inherent limitations, including their limited applicability in LHC searches for DM and lack of generality, respectively. In this study, we propose a hybrid formulation aimed at reconciling these shortcomings by addressing both generality and applicability at colliders. To this end, we introduce an EFT that incorporates DM and two scalar mediators, thereby enabling a richer phenomenology. Moreover, we formulate the theory in a non-linear phase, thereby allowing for additional representations of the scalar mediators.

To demonstrate the efficacy of this framework, we will present a comparative analysis with well-known simplified models during the talk.

Speaker: David Cabo Almeida (University of Messina (Italy))

CaboAlmeida_IDM.pdf

17:10 Spin-1 Thermal Targets for Dark Matter Searches at Fixed Target Experiments

Sub-GeV dark matter (DM) has been gaining significant interest in recent years, since it can account for the thermal relic abundance while evading nuclear recoil direct detection constraints. Such light DM must carry a larger energy to be probed, either directly or through missing energy/momentum, making beam dump and fixed target experiments ideal for this mass range. Here, we extend the previous literature, which mainly focuses on the predicted experimental signals of scalar and fermionic DM, to a set of models for spin-1 DM including a family of simplified models (involving one DM candidate and one mediator – the dark photon) and ultraviolet complete models based on a non-abelian gauge group. In this analysis, we identify the parameters consistent with the observed relic abundance, compute the relevant constraints from existing experiments, and predict the sensitivity of future experiments such as the upcoming LDMX. We find that spin-1 DM is testable by future experiments, and will be the first DM models probed by LDMX.

Speaker: Taylor Gray (Chalmers University of Technology)

IDM2024_TaylorGray.pptx

17:30 Update on WIMP Models with loop-induced Direct Detection cross-section

WIMPs are one of the most popular classes of DM candidates. However, strong tensions arise because of negative signals from Direct Detection (DD) experiments. Several WIMP modes nevertheless exist, which, until present times, could overcome this issue as the interactions relevant for DD emerge at the one loop level. I will provide an overview of such models discussing the capability of current and next generation experiments of probing their parameter space.

Speaker: Giorgio Arcadi (Istituto Nazionale di Fisica Nucleare)

IDM_arcadi.pdf

17:50 Multi-Component Dark Matter from Minimal Flavor Violation

Various experiments have confirmed with good accuracy that all flavor violating phenomena are consistent with the predictions in the Standard Model (SM) of particle physics. This empirical fact encourages us to construct new physics models based on the assumption of the Minimal Flavor Violation (MFV), which dictates that new physics interactions respect a quark flavor symmetry with the only breaking source arising from the quark Yukawa matrices. Formally, the MFV structure is achieved by promoting the quark Yukawa matrices to spurious fields non-trivially transforming under the quark flavor group.

Remarkably, it is shown that this MFV hypothesis guarantees the stability of the lightest component of a new colorless field that non-trivially transforms under the quark flavor group, thereby providing a good dark matter (DM) candidate. In this presentation, I will demonstrate that within this MFV framework, the heavier components of such a flavored field can also constitute a significant part of DM. As a benchmark, we consider a gauge singlet flavored scalar and show that the heavier components have a long enough lifetime to be DM in a parameter region. We also discuss testability of such multiple DM candidates at experiments.

Speaker: Shohei Okawa (KEK)

MFVDM_IDM2024_Okawa.pdf

18:10 Freeze-in sterile neutrino dark matter in the minimal gauge B-L model.

We study the sterile neutrino dark matter produced by the freeze-in mechanism through feeble $U(1)_{B-L}$ gauge interactions. By taking account of the contributions from the on-shell B-L scalar boson (inverse) decay and the single Z' boson production properly, we find that the cosmologically-interesting gauge coupling of $U(1)_{B-L}$ is smaller than $\mathcal{O}(10^{-10})$ if the B-L scalar kinematically can decay into two sterile neutrinos. If not, the gauge coupling of $U(1)_{B-L}$ is of $\mathcal{O}(10^{-6})$, which may be probed by long-lived particle search experiments.

Speaker: Osamu Seto

idm24_seto.pdf

16:30 → 18:50 Parallel 3: Light Dark Matter

Convener: Paolo Agnes (GSSI)

16:30 Searching for Light Dark Matter with Narrow-Gap Semiconductors: The SPLENDOR Experiment

Understanding the particle nature of dark matter, which makes up approximately 85% of the matter content in the universe, remains one of the biggest open questions in the fields of particle physics and cosmology. After decades of null results in searches for weakly interacting massive dark matter candidates, experimental and theoretical efforts have shifted towards a broad range of masses, including lighter mass dark matter candidates with masses below O(MeV). These light mass dark matter particles present a substantial detection challenge, as their relatively low kinetic energy limits the energy deposited in a target to be sub-eV. The low momentum interactions are also highly delocalized, and a detailed understanding of the collective modes of the target material is critical to predicting DM scattering rates.

The SPLENDOR Experiment (Search for Particles of Light dark mattEr with Narrow-gap semiconDuctORs) is using novel narrow-bandgap single-crystal semiconductors as ionization detectors to search for light dark matter. We have developed a series of magnetic Zintl phase semiconductors with electronic bandgaps on the order of 10-100 meV, which allow for sensitivities to fermionic (bosonic) dark matter with sub- MeV (eV) masses. The materials will are instrumented in a point contact geometry operated at mK temperatures, with the excited charge signal being read out with low-noise cryogenic HEMT based amplifiers. Our prototype charge amplifier has achieved sub-10 electron resolution and its performance is independent of detector material. In this talk I will give an overview of the SPLENDOR project, discuss our recent progress in the material synthesis and characterization, and give updates on our preliminary results.

This presentation is on behalf of the SPLENDOR collaboration and is supported by the Laboratory Directed Research and Development program of Los Alamos National Laboratory.

Speakers: Samuel Watkins (Los Alamos National Laboratory), Samuel Watkins (University of California, Berkeley)

watkins_splendor_idm2024.pdf

16:50 Direct dark matter searches using ALPS II’s TES detector system

The ALPS II light-shining-through-walls experiment at DESY in Hamburg plans to use Transition Edge Sensors (TESs) to detect low-energy single-photons originating from axion(ALP)-photon conversion with rates as low as $10^{-5}~$s$^{-1}$. Even beyond ALPS II, these superconducting microcalorimeters, operated at cryogenic temperatures, could help search for further particle-DM candidates. Much of the work to ensure the viability of the TES detector for use in ALPS II, such as calibrating the detector and mitigating external sources of backgrounds, also leads to the ability to utilize the TES for an independent direct-DM search. For this purpose, the superconducting sensor, sensitive to sub-eV energy depositions, can be used as a simultaneous target and sensor for DM-electron scattering for sub-MeV DM. Hence, direct DM searches with TES could explore parameter space as of yet inaccessible by nucleon-scattering experiments. The first calibration of the TES for sub-eV energies demonstrates promising results in the pursuit of this goal, alongside the dedicated background measurements and ensuing analysis.

Speaker: Christina Schwemmbauer (Deutsches Elektronen Synchrotron DESY)

CS_TES_DDM_IDM_2024.pdf

17:10 Development of phonon-mediated particle detectors with meV to eV energy thresholds for sub-GeV dark matter direct detection

Phonon-mediated particle detectors with sub-eV threshold reach have the potential to broadly scan the increasingly theoretically relevant sub-GeV dark matter parameter space. Two technologies we consider, Kinetic Inductance Phonon-Mediated detectors (KIPMs) and a novel scheme based on quantum computing style charge qubits called Quantum Parity Detectors (QPDs), exploit superconducting material physics via Cooper-pair breaking to sense phonons created by particle interactions within a crystalline substrate. These devices’ inherent multiplexability, non-dissipative nature, and exponential suppression of quasiparticle population with temperature – assuming a reduction in residual quasiparticles - make them well suited for imaging the entire phonon flux. We discuss recent experimental efforts in validating KIPM designs and in achieving lower thresholds, including through LED based calibrations and successes in interfacing KIPMs with quantum-limited parametric amplifiers. We also show the first signals from a QPD sensor and discuss a roadmap to potential meV-scale detectability of particle interactions by this class of device.

Speaker: Karthik Ramanathan (Washington University in St. Louis)

IDM2024_QPD_Ramanathan.pdf

17:30 Dark Matter Induced Power in Quantum Devices

Low mass dark mass search has emerged as the next frontier in the direct detection experiments. In this talk, I will describe the novel idea of using transmon qubit and other mesoscale superconducting quantum devices to detect power deposition from dark matter-nucleon scattering. I will briefly describe the power deposition calculation method, and show that the exceptional sensitivity of the existing quantum devices already allows us to put competitive limits on dark matter-nucleon scattering cross section without any dedicated dark matter experiment. Finally, I will show future projections of this limit that is achievable within next few years, and outline ways to build future collaborations in this direction.

Speaker: Anirban Das (Seoul National University)

IDM 2024 Das.pdf

17:50 BULLKID-DM: searching for light WIMP with monolithic arrays of detectors

BULLKID-DM is a new experiment to search for hypothetical WIMP-like Dark-Matter particles with mass around 1 GeV/c^2 and cross-section with nucleons smaller than 10-41 cm^2. The target will amount to 600 g subdivided in 2500 silicon dice sensed by phonon-mediated kinetic inductance detectors. With respect to other solid-state experiments in the field the aim is to control the backgrounds by creating a fully active structure and by applying fiducialization techniques. The experiment is intended to be placed at the Gran Sasso laboratories. After the encouraging results of a 20 g prototype, here we present the first results from a demonstrator array of 60 g and 180 silicon dice, the simulations of the experiment and the projected Dark Matter sensitivity.

Speaker: Marco Vignati (Istituto Nazionale di Fisica Nucleare)

BULLKID-DM IDM 2024.pdf

21:00 → 22:30 Concert: I Solisti Aquilani

Wednesday, 10 July

09:00 → 10:30 Plenary

Convener: Laura Baudis

09:00 Dark Matter: theoretical framework and particle candidates

I review the status of dark matter theory, and present a series of challenges for the discovery road ahead.

Speaker: Kathryn Zurek (Caltech)

24_IDM.pptx

09:30 Experimental Dark Matter search at mass > 1 GeV

This talk will present an overview of the experimental efforts to detect WIMP dark matter and other particle candidates with masses above 1 GeV, along with the prospects for finally identifying the nature and origin of dark matter.

Speaker: Maria Elena Monzani (SLAC National Accelerator Laboratory)

MEM-IDM-10Jul24.pdf

XEnT-Poll-Results.pdf

10:00 Experimental Dark Matter searches at the GeV scale

This talk will focus on recent advancements in dark matter searches at the GeV scale. I will present the latest results from major experiments, such as those conducted at underground laboratories and physics facilities, emphasising the detection mechanisms and the methods used to identify potential dark matter signals over backgrounds. Additionally, the talk will explore future prospects and technological innovations designed to enhance sensitivity and detection capabilities.

Speaker: Lucia Canonica (University of Milano Bicocca & INFN)

IDM2024_Canonica.pdf

10:30 → 11:00 Coffee break

11:00 → 12:30 Plenary

Convener: Daniel McKinsey

11:00 Experimental dark matter searches at masses below the GeV mass scale

In the absence of a verifiable dark matter signal in traditional direct detection or collider experiments, parallel theoretical and experimental advancement has unlocked the possibility of searching for particle dark matter lighter than the proton. In the past decade, this has allowed for rapid development of charge detection in traditional materials with eV-scale band gaps. Ongoing detector R&D into novel materials and sub-eV thresholds further expands the phase space of direct detection. I will provide an overview of these experimental efforts to search for ‘Light Dark Matter’ below the GeV mass scale.

Speaker: Daniel Baxter (Fermi National Accelerator Laboratory)

lowmass_071024.pdf

11:30 Low Energy Excess(es) in Cryogenic Detectors

Low mass dark matter searches and coherent neutrino-nucleus scattering experiments using low-threshold cryogenic detectors observe excess of events at low energies close to their thresholds. This background, dubbed the Low Energy Excess, limits the sensitivity of these experiments. There has been a worldwide effort to understand the origin of these events over the past years. I will report on the various observations of the different experiments and discuss some of the hypotheses trying to explain the excess that are currently being tested.

Speaker: Christian Strandhagen (University of Tübingen)

Strandhagen-IDM-LEE-cryodetectors.pdf

12:00 New results from XENONnT

Speaker: Fei Gao (Tsinghua University)

xenonnt-cevns-newresults-idm-2024.pdf

12:30 → 14:00 Lunch

14:00 → 16:20 Parallel 1: Light Dark Matter

Convener: Paolo Agnes (GSSI)

14:00 Direct Dark Matter search with the CRESST-III experiment: Status and Prospects

CRESST-III (Cryogenic Rare Event Search with Superconducting Thermometers) is an experiment at the LNGS underground laboratories looking for direct detection of dark matter particles via their scattering off target nuclei in cryogenic detectors. Reaching energy thresholds of less than 100 eV, CRESST-III is among the leading experiments in probing sub-GeV DM masses. However, an unexplained rise of events at low energies (<200 eV) is currently limiting the sensitivity of the experiment in the low mass region. Therefore, for both the last measuring campaign, which ended in February 2024, and the new measuring campaign, which started in April 2024, the focus has been set on investigating the origin of this “low energy excess” (LEE). In this contribution we present an overview of CRESST-III, reporting on the latest results and future plans.

Speaker: Anna Bertolini (Max-Planck-Institut für Physik)

CRESST_IDM24.pdf

14:20 Updates and latest results of the SENSEI experiment

The sub-electron resolution of Skipper-CCDs enables the detection of energy transfers as low as a few eV, such as what is expected from sub-GeV dark matter interacting with electrons in a silicon target. SENSEI pioneered implementing these sensors in rare-event searches, producing several world-leading results with this technology and setting a new benchmark with the lowest reported dark current in a silicon detector. In this talk, we present SENSEI's status and discuss recent results.

Speaker: Ana Martina Botti (Fermilab)

SENSEI@IDM-7.pdf

14:40 Light Dark Matter searches with a next generation Spherical Proportional Counter

The NEWS-G collaboration is searching for light dark matter candidates using spherical proportional counters. Access to the mass range from 0.05 to 10 GeV is enabled by the combination of low energy detection threshold, light gaseous targets (H, He, Ne), and highly radio-pure detector construction.

Initial NEWS-G results obtained with SEDINE, a 60 cm in diameter spherical proportional counter operating at LSM (France), excluded for the first time WIMP-like dark matter candidates down to masses of 0.5 GeV.
Currently, a 140 cm in diameter spherical proportional counter, S140, constructed at LSM using 4N copper with 500 μm electroplated inner layer, operates in SNOLAB (Canada) with the first physics campaign recently completed. The first physics results using commissioning data will be presented along with the developments in read-out sensor technologies using resistive materials and multi-anode read-out that enable its operation.

Moreover, recent developments on the detector instrumentation, namely individual read-out of the multi-anode sensor and electroformation techniques, will be discussed towards DarkSPHERE, a large-scale spherical proportional counter fully electroformed underground at the Boulby Underground Laboratory.

Speaker: Ioannis Manthos (University of Hamburg)

SPC_IDM_Manthos.pdf

15:00 Results with Low Background Chamber, a DAMIC-M prototype

The DAMIC-M (DArk Matter In CCDs at Modane) experiment employs a novel technique to search for the elusive particles which make up most of the matter in the universe, called dark matter. The aim is direct detection of light dark matter (WIMPs, Hidden Sector Particles) via interaction with silicon in the bulk of the CCDs (Charged Coupled Devised). These CCDs use skipper amplifiers to non-destructively measure charge multiple times to provide single electron resolution, pushing our detection threshold to a few eVs.
The LBC (Low Background Chamber), a prototype detector of DAMIC-M, containing 20g target silicon CCDs, was commissioned near the end of 2021 at the Laboratoire Souterrain de Modane. After two successful science runs, LBC was able to set unparalleled exclusionary limits on dark matter-electron scattering interactions. The LBC was utilized to study the background rates and to compare them with simulations, which gives us a clear pathway for further mitigation of background. This talk would focus on the first results and background analysis with the prototype LBC.

Speaker: Dr Danielle Norcini (Chicago)

240710_damicm_lbc.pdf

15:20 The SuperCDMS experiment at SNOLAB

The existence of dark matter is strongly indicated by various astronomical observations. However, its exact nature and properties are yet to be discovered. The SuperCDMS experiment, currently being built 2 km underground at SNOLAB in Canada, is a collaborative scientific effort to search for dark matter via direct detection. It will employ an array of silicon and germanium crystals instrumented with either phonon sensors, called HV detectors, or, phonon and charge sensors, called iZIP detectors. HV detectors make use of the Neganov-Trofimov-Luke effect to amplify phonon signals, thereby achieving a lower energy threshold. iZIPs are capable of exquisite electronic versus nuclear recoil discrimination thus reducing background effectively. Combining these two detector types gives the SuperCDMS experiment a unique potential to probe low mass, low cross-section dark matter particles. In this talk, I will give an overview of SuperCDMS detector technologies and its scientific reach.

Speaker: Sukeerthi Dharani (KIT / UHH)

IDM2024_SDharani_SuperCDMS_SNOLAB.pdf

15:40 The ionization-signal-only analysis and results in PandaX-4T experiment

The ionization-signal-only can lower the energy threshold of the liquid xenon time projection chamber. In this talk, we will report the results of light dark matter searching with ionization-signal-only in the PandaX-4T experiment. In addition, we investigated the source of the dominant backgrounds, including cathode and micro-discharging backgrounds, in ionization-signal-only events with PandaX-4T data.

Speaker: Shuaijie Li (Yalong Hydro)

IDM-lsj-v2.pdf

16:00 Towards discovery of hidden sector dark matter with liquid xenon TPCs

The first direct detection limits on sub-GeV dark matter utilized electron counting data from the XENON10 liquid xenon TPC. For over a decade, progress in the sensitivity of these instruments to sub-GeV dark matter has been hampered by delayed electron noise. In this talk, we will show new data indicating the origin of the delayed electron noise and the path to its mitigation. We will conclude with projections for search sensitivity beyond the freeze-in target for hidden sector dark matter candidates.

Speakers: Peter Sorensen (LBL), Ryan Gibbons (LBL)

Sorensen-IDM-2024.pdf

14:00 → 16:20 Parallel 2: Astrophysical observations

Convener: Riccardo Biondi (Istituto Nazionale di Fisica Nucleare)

14:00 New Challenges Facing Pulsar Interpretations of the Galactic Center Gamma-Ray Excess

Abstract: It has been suggested that the Galactic Center gamma-ray excess could be produced by a large number of centrally-located millisecond pulsars. The fact that no such pulsar population has been detected implies that these sources must be very faint and very numerous. Using Fermi’s recently released Third Pulsar Catalog, we measured the luminosity function of the millisecond pulsars in the Milky Way’s Disk. If the gamma-ray excess were generated by millisecond pulsars with the same luminosity function, ~20 such sources from the Inner Galaxy population should have already been detected by Fermi. Given the lack of such observed sources, the hypothesis that the gamma-ray excess is generated by pulsars with the same luminosity function is excluded with a significance of 3.4σ. We conclude that either less than 39% of the GCE is generated by pulsars, or that the millisecond pulsars in the Inner Galaxy are at least 5 times less luminous (on average) than those found in the Galactic Disk.

Speaker: Dan Hooper (Fermilab/University of Chicago)

IDM-2024-Pulsars.pdf

14:20 Limits on Asteroid Mass Primordial Black Holes via fast microlensing

A galactic halo population of Primordial black holes (PBH) are a simple solution to the dark matter (DM) problem. Being dark, massive and non-baryonic, the PBH fits within the phenological traits that define Cold Dark Matter, and may exist in large numbers in the dark halos of spiral galaxies. Gravitational microlensing is among the most productive experimental avenues to constrain the galactic PBH abundance in the mass regime from ~ 10−12 M⊙ (i.e. asteroid-mass scale) to ∼ 1000 M⊙. The key to probing the very lowest masses is fast cadence observations on the order of hours to minutes. We previously conducted a 5-night DECam survey of the Large Magellanic Cloud (LMC), monitoring 2 million LMC stars in a single very broad optical filter to a limit of r ≈ 23 at ≈ 40 second cadence, with the primary motivation being to place constraints on the PBH abundance in the Galactic halo in the asteroid- to Jupiter-mass regime (−12 ≲ logM/M⊙ ≲ −4). This talk will present the most stringent results on asteroid-mass PBHs in the Milky Way halo by incorporating considerations of second-order realistic corrections to the microlensing signal, such as finite source effects and wave optics. The main discussion of this talk will be the detection pipeline, a discussion on the pipeline efficiency and 95% C.L on the fraction of PBHs that exist as halo DM within the standard halo model.

Speaker: Renee Key (Swinburne University of Technology)

IDM2024.pdf

14:40 Tracing Cosmic Evolution through Dark Matter Phenomena: Insights from Primordial Black Holes and Supermassive Dark Stars

The James Webb Space Telescope (JWST) has dramatically advanced our understanding of cosmic history, revealing new aspects of dark matter (DM) phenomena, particularly through our studies on Primordial Black Holes (PBHs) and Supermassive Dark Stars (SMDSs). These studies enhance our knowledge of the dark sector's role in the early universe and serve as an indirect probe for DM.
Our research utilizes N-body simulations with the GIZMO code and semi-analytical models to investigate PBHs' impact. We find that stellar-mass PBHs, ranging from 10-100 $M_{\odot}$ and constituting a fraction of $10^{-4}$ to $0.1$ of DM, subtly influence the formation of the universe’s first stars by maintaining the standard model of star formation, while their accretion feedback shifts star formation to more massive halos. Additionally, PBHs significantly contribute to the cosmic radiation background during reionization and might facilitate the formation of direct-collapse black holes. On the other hand, more massive PBHs with $10^6 M_{\odot}$, could seed massive halos and disrupt hierarchical structure formation by engulfing newly formed halos.
Conversely, SMDSs, powered by DM and primarily consisting of hydrogen and helium, form at redshifts around $z \sim 10-20$. Using the Roman Space Telescope (RST), we could detect SMDSs up to $z \simeq 14$. The distinction between SMDSs and early metal-free galaxies relies on spectral, photometric, and morphological analyses, with the HeII $\lambda$1640 absorption line serving as a smoking gun. Identification of SMDS candidates by the RST photometry, complemented by JWST spectroscopy, could confirm the existence of a novel star class and illuminate the origins of supermassive black holes underlying ancient quasars.

Speaker: Saiyang Zhang (University of Texas, Austin)

Formation of Supermassive Black Hole.pptx

15:00 Probing the nature of Dark Matter with the first stars and galaxies in the Universe

Launched at the end of 2021, the James Webb Space Telescope (JWST) has already begun to revolutionize our view of the cosmic dawn era. Specifically, it discovered an unexpectedly large number of extremely bright objects in the sky from the early Universe, whose light was emitted more than thirteen billion years ago. If these objects are interpreted as some of the first galaxies ever assembled, their discovery would be in stark contrast with the expectation set by numerical simulations, which predicted such bright galaxies to have formed significantly later. For this reason, those JWST objects are sometimes mistakenly called "cosmology breakers." In fact, in view of HST data, which highly disfavors a cosmological solution to this problem, it would be more appropriate to call them "astrophysics benders." In addition, a combination of IR and X-ray data data further strengthen another problem in astrophysics: the origin of the supermassive black holes that power the large number of very bright quasars observed when the Universe was younger than 900 Myrs. Combined, those two problems indicate that the current understanding of the formation of the first stars and galaxies is, at best, incomplete. However, this ``understanding'' is largely based on theoretical and numerical models that ignore the role Dark Matter can play on the formation of the first stars. In 2008 Spolyar, Freese, and Gondolo [Phys. Rev. Lett. 100, 051101] have shown that the heat due to the annihilation of Weakly Interactive Massive Particles (WIMPs) at the center of high redshift Dark Matter halos can halt the collapse of zero metallicity protostellar gas clouds. In other words, a new kind of star can form, powered exclusively by Dark Matter annihilations. In view of their power source, those objects are called Dark Stars, although, they can be as bright as a galaxy and grow as massive as a million Suns. In this talk I will review the theoretical and observational status of Dark Stars and show how they can be natural solutions to both of the puzzles described above. Specifically, I will demonstrate how Dark Stars can provide natural massive Black Hole seeds needed to explain the most distant quasars ever observed, such as UHZ1. I will also discuss the three Supermassive Dark Star candidates already identified with JWST (JADES-GS-z-13, JADES-GS-z12, and JADES-GS-z-11) [PNAS 120 (30)] and prospects for spectroscopic confirmation of Dark Stars. The unambiguous detection of any such object, via any of its spectroscopic smoking gun signatures (such as the HeII1640 absorption) would imply the first non-gravitational confirmation of the existence of Dark Matter.

Speaker: Cosmin Ilie (Colgate University)

ILIE First Stars as DM Probes IDM 24.pdf

15:20 Immortal Stars at the Galactic Center

Dark matter can be captured in stars and annihilate, providing the star with a new energy source in addition to nuclear fusion. This significantly changes stellar evolution at the Galactic Center, where the dark matter density is extremely high. As dark matter burning replaces nuclear fusion partially or completely, stars become longer-lived, as they use up hydrogen more conservatively, or even become immortal, as dark matter is re-supplied continuously. We show that this results in several prominent features that distinguish stellar populations in dark matter dense environments from populations without dark matter. This may offer an explanation for the unusually young stars at the Galactic Center, called the paradox of youth, as well as their top-heavy mass distribution. In some scenarios, the dark matter annihilation power can become so intense to disrupt star formation entirely, allowing us to derive constraints on dark matter-nucleon cross sections and density profiles based on stellar observations close to the Galactic Center.

Speaker: Isabelle John (Stockholm University)

IDM_2024_IsabelleJohn.pdf

15:40 Constraining dark matter annihilation with Fermi-LAT observations of Ultra-Faint Compact Stellar Systems

Recent observations from optical surveys have discovered the presence of a multitude of ultra-faint compact stellar systems (UFCSs) orbiting the Milky Way (MW) that have the potential to be the most compact and faintest galaxies observed so far. If they were confirmed to be dark matter (DM) dominated, these objects would be ideal for indirect searches of DM annihilation, due to their proximity and relatively high DM content. We analyze 14.3 years of Fermi-LAT gamma-ray data coincident with 26 UFCSs, selected using the results from recent numerical simulations and models of galaxy formation. No excess gamma-ray emission is detected and we evaluate the gamma-ray flux upper limits for these systems. We derive the sensitivity for DM annihilation signal, assuming that these UFCSs are DM-dominated and consistent to the observed population of dwarf spheroidal satellite galaxies (dSphs) of the MW. We also account for the possibility that not all the targets in our sample are DM-dominated, by evaluating the sensitivity for random subsets of the selected UFCSs. This work shows the potential of the UFCSs to yield constraints on DM properties that are competitive with, if not improve, the ones obtained from dSphs, and highlights the importance of kinematic studies on these systems to empirically determine their DM content.

Speaker: Antonio Circiello (Clemson University)

Circiello_IDM_2024.pdf

16:00 CosmiXs: Cosmic messenger spectra for indirect dark matter searches

The energy spectra of particles produced from dark matter (DM) annihilation or decay are one of the fundamental ingredients to calculate the predicted fluxes of cosmic rays and radiation used for indirect DM detection. We revisit the calculation of the source spectra for annihilating and decaying DM employing the Vincia shower algorithm in Pythia to include QED and QCD final state radiation and diagrams for the electroweak corrections with massive bosons, not present in the default Pythia shower model. We take into account the spin information of the particles during the entire electroweak shower and the off-shell contributions from massive gauge bosons. Furthermore, we perform a dedicated tuning of the Vincia and Pythia parameters to LEP data on the production of pions, photons, and hyperons at the resonance and discuss the underlying uncertainties. To enable the use of our results in DM studies, we provide the tabulated source spectra for the most relevant cosmic messenger particles, namely antiprotons, positrons, gamma rays and the three neutrino flavours, for all the fermionic and bosonic channels and DM masses between 5 GeV and 100 TeV, on GitHub (https://github.com/ajueid/CosmiXs.git).

Speaker: Mattia Di Mauro (Istituto Nazionale di Fisica Nucleare)

IDM_Cosmixs_dimauro.pdf

14:00 → 16:20 Parallel 3: Axion/Sterile

Convener: Carla Macolino (Istituto Nazionale di Fisica Nucleare)

14:00 Indirect Detection of the QCD Axion: Resonant Conversion in Neutron Star Magnetospheres

The Peccei-Quinn mechanism addresses the strong charge-parity problem in particle physics by postulating the existence of the QCD axion, a heretofore undetected particle that would interact with known particles. In particular, axion-photon coupling would enable axion-photon conversion in the presence of a magnetic field. Detecting axions requires strong magnetic fields, dense dark matter environments, and instruments capable of measuring the brightness and frequency of emitted photons. Radio telescopes offer a promising avenue for detection, especially in regions rich with young neutron stars. I discuss recent progress in the field from both theoretical and detection perspectives, focusing on results obtained by employing the VEGAS spectrometer on the Green Bank Telescope to investigate axion-photon conversions near the core of the Andromeda galaxy.

Speaker: Luca Visinelli (Shanghai Jiao Tong University)

Visinelli IDM 2024.pdf

14:20 Improved bounds on the hot QCD axion

The QCD axion is the most robust explanation to the strong CP problem and provides a good dark matter candidate. A population of QCD axions can be produced in the early universe via scattering with SM particles, and can be searched for in cosmological datasets. I will present the state-of-the-art bound on the minimal QCD axion model by confronting momentum-dependent Boltzmann equations, from axion-pion scattering below the QCD cross-over, against up-to-date measurements of the CMB and abundances from BBN. Finally, I will present forecasts using dedicated likelihoods for future cosmological surveys and a new sphaleron rate from unquenched lattice QCD.

Speaker: Giovanni Grilli di Cortona (Istituto Nazionale di Fisica Nucleare)

Grilli_hotQCDaxion.pdf

14:40 Searching for axion dark matter from dwarf spheroidal galaxies and the Sun

The coupling of axion and axion-like particles (ALPs) to two photons leads to radiative decays of axion dark matter and axion-photon conversion in an external magnetic field. We discuss two methods to search for these signals exploiting astrophysical data. The first is based on MUSE spectroscopic optical observations of a sample of five classical and ultra-faint dwarf spheroidal galaxies.
We present world-leading limits on ALPs radiative decays for ALPs masses in the range of 2.7-5.3 eV. The second strategy relies on the radio emission produced from the conversion of ALPs in the Sun’s magnetic field, including conversion in sunspots. We demonstrate that near-future low-frequency radio telescopes, such as the SKA Low, may access regions of unexplored parameter space for masses below the micro-eV range.

Speaker: Marco Taoso (Istituto Nazionale di Fisica Nucleare)

MTaoso_IDM.pdf

15:00 Electron Trap as Dark Matter Detector

Ultralight dark matter, such as axion and dark photon, in the milli-eV mass range, is notoriously difficult to detect. It is too high in frequency for high-$Q$ cavity resonators yet below the energy threshold of single-photon detectors. Our recent work (arXiv:2208.06519) showed that the cyclotron motion of trapped electrons can resonantly couple to dark photon and provide a powerful probe of this mass range. The effect is enhanced by the geometric focusing of a spherical cavity. We demonstrated the method is background-free over a 7-day period. I will also present some new ideas for improving this method and modifying it to search for axion.

Speaker: Samuel S. Y. Wong (Stanford University)

Electron Trap as a Dark Matter Detector IDM2024.pdf

15:20 First results and future prospects of the Laser-Interferometric Detector for Axions (LIDA)

We present the operating principle and the first results of a novel direct detector for axions and axion-like particles that is sensitive to the polarisation axis rotation of a linearly polarised laser field induced by an axion field. During its first observing run, LIDA reached a competitive sensitivity of up to 1.5 x 10^(-10) GeV^(-1) around masses of 2 neV, which coincides with predictions from the cosmic infrared background. We discuss future plans to increase the sensitivity, especially by broadening the measurement band significantly towards lower axion masses of 10^(-16) to 10^(-10) eV and by implementing a squeezed light source. Finally, we present the proposal to transform the gravitational-wave detector and technology testbed GEO600 in Germany into a kilometre-scale upgrade of LIDA which could even surpass the most stringent constraints of astrophysical observations between axion masses of 10^(-16) and 10^(-8) eV.

Speaker: Joscha Heinze (University of Birmingham)

Heinze_LIDA_IDM_2024.pdf

15:40 Current status and future plans of Dark matter Axion search with riNg Cavity Experiment (DANCE)

Axion and axion-like particles are leading candidates of dark matter. Axion weakly interacts with photon, electron, proton and so on. Although many experiments have been proposed by utilizing the axion-photon conversion under magnetic fields, axion has not been observed yet.
Recently, our research group has proposed Dark matter Axion search with riNg Cavity Experiment (DANCE). DANCE aims to detect axion dark matter with axion mass $m_a$ in the range $10^{-17} \le m_a \le 10^{-10}$ eV without using the background magnetic field. In the presence of axion dark matter, the axion-photon interaction induces a rotation of linearly polarized light. We aim to detect the amplified rotation angle with a bow-tie optical ring cavity. In the prototype experiment, DANCE Act-1 with a round-trip length of 1 m, the reflection phase difference between s-polarization and p-polarization on the mirrors of the cavity was observed. This was due to oblique incidence on the mirrors, and we were not able to achieve simultaneous resonance, which is necessary to conduct a sensitive broadband axion search. Recently, we achieved simultaneous resonance by adding an auxiliary cavity to compensate for the reflection phase difference. However, the optical loss on the polarization beam splitter between a bow-tie optical ring cavity and an auxiliary cavity degrades the sensitivity to axion. Also, the measurement results of DANCE Act-1 revealed the time drift of the reflection phase difference between polarizations on the mirrors of the cavity. This makes it challenging to conduct an accurately sensitive axion search.
An alternative approach to address these issues is to tune the reflection phase difference between polarizations by tuning laser wavelength. This approach achieves simultaneous resonance by canceling the reflection phase difference between polarizations when light is reflected on the mirrors. In this talk, I will report the current status and future plans of DANCE.

Speaker: Hinata Takidera (Department of Physics, University of Tokyo)

20240710_IDM2024_Takidera_v3.pdf

16:00 HyperLSW – Experimental Setups for Determining the Amount of Axion Dark Matter After a Discovery

QCD axions and axion-like particles are increasingly popular dark matter (DM) candidates, and experiments are closing in on the most interesting regions of parameter space. Still, even after a discovery in a haloscope, we would usually not be able to determine their local DM abundance. In this talk, I will introduce HyperLSW, a class of ambitious light-shining-through-a-wall follow-up experiments to break the degeneracy between the axion-photon coupling and the axion’s local DM abundance. I will estimate the sensitivity of such experiments, showing that they can reach the QCD axion band, by addressing their inherent challenges and demonstrating their feasibility. To conclude, I will briefly comment on the post-discovery potential of axions as messenger particles in astrophysics.

Speaker: Sebastian Hoof (Università degli Studi di Padova)

2024_idm_hoof.pdf

16:20 → 17:30 Poster session: Coffee Break, Poster session, Outreach projects exhibit

16:20 Neutrinos from the Sun can discover dark matter-electron scattering

Dark matter (DM) particles can get captured inside the Sun due to DM-electron interaction. As the number of these captured DM particles increases, they can annihilate and produce different Standard Model (SM) final states. Neutrinos and anti-neutrinos produced from these final states can escape the Sun and reach ground-based neutrino telescopes. The latest data-sets from IceCube and DeepCore show no such excess of high energy neutrinos from the solar direction. Using these data-sets, we put stringent constraints on DM-electron scattering cross sections in the DM mass range 10 GeV to 10$^5$ GeV. Thus, near-future observations of the Sun by neutrino telescopes can potentially discover DM-electron interaction.

Speaker: Akash Kumar Saha (Centre for High Energy Physics (CHEP), Indian Institute of Science, Bengaluru, India)

DM_e_Scattering_IDM.pdf

16:25 PRyMordial: A tool for Dark Sectors in the Early Universe

In this presentation, we introduce PRyMordial: a specialized tool designed for efficient computations of observables in the Early Universe, specifically focusing on the cosmological epoch of Big Bang Nucleosynthesis (BBN). We will succinctly outline the key features of the package, emphasizing its ability to rapidly and accurately evaluate BBN light-element abundances alongside the effective number of relativistic degrees of freedom, accounting for non-instantaneous decoupling effects. The majority of our discussion will be dedicated to demonstrating how PRyMordial facilitates comprehensive investigations into New Physics active during BBN, with a particular emphasis on the physics of Dark Sectors.

Speaker: Mauro Valli (Istituto Nazionale di Fisica Nucleare)

16:45 Detecting quadratically coupled ultralight dark matter with stimulated annihilation

Ultralight dark matter (ULDM) is one of the most promising DM candidates. Because of the Bose enhancement, we find the annihilation rate of ULDM in the presence of background photon radiation can be greatly enhanced and produce a distinctive reflected electromagnetic wave with an angular frequency equal to the ULDM mass. We propose to utilize such stimulated annihilation to probe the ULDM with the electromagnetic quadratic coupling by emitting a radio beam into space. With a power of a 50 MW emitter, we forecast the sensitivity of quadratic coupling in different local halo models for low-frequency radio telescopes, such as LOFAR, UTR-2, and ngLOBO.

Speaker: Yuanlin Gong

17:05 Polarization Signals from Axion-Photon Resonant Conversion in Neutron Star Magnetosphere

Neutron stars provide ideal astrophysical laboratories for probing new physics beyond the Standard Model. If axions exist, photons can develop linear polarization during photon-axion conversion in the magnetic field of a neutron star. We find that the plasma in the neutron star magnetosphere could dramatically enhance the polarization through the resonant conversion effect. With the polarization measurements from PSR B0531+21, PSR B0656+14, and 4U 0142+61, we derive new strong constraints on the axion-photon coupling in a broad axion mass range $10^{-11}\lesssim m_a \lesssim 10^{-3}$ eV.

Speaker: Liangliang Su (Nanjing Normal University)

17:10 A novel low-energy calibration method for light Dark Matter searches and CEνNS cryogenic experiments: the CRACK project

Light dark matter searches and CEνNS experiments require thresholds of a few eVs, which pose the crucial challenge of calibrating such low energies. In this poster we present the status of the CRACK project, which develops an innovative method to calibrate cryogenic detectors in the range of eV without adding any permanent background to the experiments. It is based on a miniaturized particle-induced X-ray emission (PIXE) system with short half-life alpha emitters for low-threshold rare events cryogenic experiments, solving a problem faced by many other cryogenic experiments like CRESST.

Speaker: Dr Pedro Guillaumon (Max-Planck-Institut für Physik)

17:10 A skipper-CCD light shield for dark matter detection in space

Skipper-CCDs serve as ultra-low energy threshold detectors increasingly used for rare event searches. Exploring their potential for operation in space to detect electron recoils from strongly interacting sub-GeV dark matter and X-ray signatures of dark matter annihilation or decay raises novel challenges. In this work, we present advancements in the design of Skipper-CCD sensors tailored for operations in environments with high optical background levels, such as those expected in space. These packages incorporate a custom-made aluminum shield placed on the CCD surface that successfully blocks over 99.9% of visible light while preserving the efficiency for >keV X-rays.

Speaker: Ana Martina Botti (Fermilab)

17:10 A state-of-the-art many-body atomic response of xenon and germanium atom used for direct dark matter detection

In recent years, significant strides have been made in direct dark matter detection experiments, driven by advancements in detector technologies and the scaling up of detector sizes, predominantly motivated by the Weakly Interacting Massive Particle (WIMP) paradigm. In the realm of dark matter (DM) scattering processes, understanding the contributions from electronic and nuclear degrees of freedom is crucial. While the prevailing approach in constraining DM interactions typically focuses on one type at a time, it's essential to acknowledge that detector-measured events stem from a confluence of potential sources.
Moreover, it is essential from an experimental standpoint to ascertain the optimal process and kinematic range for constraining specific types of dark matter interactions with electrons or nucleons. Achieving this necessitates reliance on theoretical analysis. In this study, we endeavor to tackle these inquiries utilizing atomic detectors, notably Germanium and Xenon, where calculations are predominantly feasible using nonrelativistic effective field theory. We calculate and examine their scattering with nonrelativistic light dark matter (LDM) particles spanning a mass range from MeV to GeV. The sub-GeV dark matter regime remains relatively underexplored yet holds significant promise for next-generation experiments. Our investigation delves into computing the atomic response function (ARF) of target atoms like Germanium and Xenon, pivotal for the operation of DM search experiments and the exploration of DM-electron interactions. Employing an approach grounded in ab initio calculations within the framework of the multi-configuration relativistic random-phase approximation (MCRRPA) and Frozen Core Approximation (FCA), we unveil that the ionization rate of atoms via DM-electron scattering can generally be delineated by four independent atomic responses. Specifically, we present ARF for DM-atom scattering through interactions at the leading order (LO), leveraging robust, state-of-the-art atomic many-body calculations. Our novel atomic responses demonstrate numerical significance across various scenarios, such as the investigation of light-dark matter (LDM) particle scattering with atomic electrons within the effective field theory framework. Subsequently, we utilize these atomic responses to establish 90 percent confidence level (C.L.) exclusion limits on the strength of a wide array of DM-electron interactions, inferred from the null results of DM search experiments utilizing Germanium and Xenon targets. Our computations yield differential cross-sections within a 5% error margin in RRPA and 20% in FCA, underpinning the reliability and precision of our findings.
This endeavor received support from the National Taiwan University and the National Science and Technology Council (NSTC) of Taiwan.

Speaker: Dr Mukesh Kumar Pandey (Department of Physics, National Taiwan University)

17:10 Analysis of the CRESST warm-up test data

The Cryogenic Rare Event Search with Superconducting Thermometers (CRESST) is one of the most sensitive experiments for the direct detection of light dark matter via nuclear recoils. At low recoil energies below roughly 200eV, the sensitivity is affected by the presence of an increasing event rate for which dark matter as a major contribution has already been ruled out. Such a low energy excess (LEE) is not only observed in all CRESST detectors but also in other cryogenic experiments, so far without a definitive answer to what the origin is.

Between Oct. 2021 and Feb. 2024, CRESST has performed dedicated studies on the behavior of the excess by warming up the cryostat to different temperatures, alternating with periods of data taking. We will present the current status of the corresponding analysis, which utilizes two-dimensional unbinned fits on time and energy simultaneously. A focus lies on the temporary rises and following decays in the LEE event rate that have been observed to occur after such warm-ups.

Speaker: Sarah Kuckuk (Universität Tübingen)

CRESST_LEE_SKuckuk.pdf

17:10 Atom interferometer searches for spin-2 ultra-light dark matter

Atom interferometers are a new class of quantum sensors capable of making precision measurements in many areas of fundamental physics including gravitational wave and ultra-light dark matter (ULDM) searches. While the sensitivity of atom interferometers to scalar ULDM has been established [arXiv: 1911.11755; arXiv: 2308.10731], spin-2 ULDM models are also well motivated but have yet to be fully explored. In this talk I will outline the phenomenology of spin-2 ULDM in atom interferometers and discuss how best to optimise searches by operating multiple experiments in a network. Existing laser interferometer searches for spin-2 ULDM will be complemented by atom interferometers by probing different mass parameter space and offering a distinct method of detection. Not only will spin-2 ULDM induce a change in the laser phase measured in the interferometer but will additionally couple directly to the internal energy states of the atoms. Atom interferometers are uniquely sensitive to both effects, which will enhance the limits these experiments will place on spin-2 ULDM and help distinguish these signals from scalar candidates. Work in collaboration with Diego Blas and Christopher McCabe.

Speaker: John Carlton (King's College London)

IDM_spin2_poster_John_Carlton.pdf

17:10 Background mitigation with PICO-500

Modern bubble chambers offer a unique opportunity to probe the dark matter parameter space through the use of superheated C₃F₈ as the target material. PICO-500 is the next generation of bubble chamber detector made by the PICO collaboration. It will be located at the underground research facility SNOLAB in Sudbury, Canada. Backed by the operational experience of previous detectors, PICO-500 will be an improvement over previous detectors on many fronts including size and design. Bubble nucleation requires highly localized energy deposition, making PICO-500 insensitive to electron at the operated energy threshold. This leaves the focus on background rates to alpha and neutron particles. Background rates were among the limiting factors of previous detectors. New mitigation techniques are going to be used in the assembly of PICO-500, most notably for radon mitigation. The high radon concentration in the underground lab makes it a difficult task to limit the exposure time to this background. During the assembly of the detector, nylon bags flushed with nitrogen will be used to limit the deposition of radon on the surfaces of the bubble chambers active region. In this talk, an overview of the detector design, its improvement from previous, background mitigation techniques and expected background rates following mitigation will be presented.

Speaker: Jeremy Savoie (Université de Montréal)

PICO - Radon Mitigation - JSavoie.pdf

17:10 Bringing Back the Senses to LUX-ZEPLIN

The LUX-ZEPLIN (LZ) experiment set world-leading limits for spin-independent WIMP-nucleon interactions above 10 GeV/$c^2$, with its first science run results released in 2022. Background characterisation and a complete understanding of the detector and internal conditions is vital to achieve and improve upon such limits; in the chance of discovery, these are a necessity to provide a foundation for the result. LZ utilises a dual-phase time projection chamber (TPC) with 7 tonnes of active xenon to generate and image signals within the detector. Acoustic sensors; loop antennae; and weir-level sensors were developed and installed on the detector to monitor the vibrational and electromagnetic environments as well as detect the presence of any surface waves within the TPC.

I will showcase the first studies into monitoring the internal conditions of the TPC using these sensors, including any correlations found between these conditions and backgrounds observed.

Speaker: Anthony Swain (University of Oxford, LZ Experiment)

AnthonySwainPoster.pdf

17:10 Bulk Acoustic Wave devices for high-frequency gravitational wave antennas

High-frequency gravitational wave (GW) detection based on a cryogenic bulk acoustic wave (BAW) cavity coupled to a superconducting quantum interference device (SQUID) has been under investigation at the University of Western Australia for several years. A recent paper reported the observation of rare events of uncertain origin using the first antenna of this type. In this report, we describe the work towards the construction of a similar GW antenna at the University of Milano Bicocca, including the characterisation of commercially available BAWs and plans to tailor the BAWs to sample multiple frequencies from about 0.5 MHz to a few tens of 1 MHz. Potential GW sources in this range include scenarios involving dark matter candidates such as primordial black hole binaries and axion-black hole interactions.

Speaker: Lucia Canonica (Università di Milano Bicocca)

17:10 Characterization of DarkSide-20k large-area SiPM Tiles

One of the most challenging open problems in physics is the direct detection of dark matter candidates. Several low-background underground experiments are currently involved in the search of Weakly Interacting Massive Particles (WIMP) employing noble liquids like xenon or argon that have very good scintillation properties. High-performance single-photon detectors are required to acquire the faint signals emitted by the expected interaction of such candidates in the detector.
DS-20k detector is a double-phase Time Projection Chamber (TPC) containing 20 tons of ultrapure liquid argon in the fiducial volume. The scintillation light emitted by particles interacting with argon in the TPC will be read out by custom developed, cryogenic, low-noise grouped arrays of Silicon Photo Multipliers (SiPMs). The TPC will be equipped with 21 m$^2$ of active surface and 5 m$^2$ will be installed in the surrounding active veto.
The mass production of the SiPM sensors will occur at the Nuova Officina Assergi at Laboratory Nazionali del Gran Sasso, a brand new facility including a 400 m$^2$ clean room. This talk will report about the characterization of the $5 \times 5$ cm$^2$ SiPM Tiles of DS-20k, currently underway. Preliminary yield of tested pre-production Tiles is approaching 90%. Furthermore, the first measurements of the Dark Count Rate of large area SiPM-based photodetectors will be presented. Our preliminary analysis exhibits DCR values of the order of 1 Hz/cm$^2$.

Speaker: Andrea Marasciulli (Istituto Nazionale di Fisica Nucleare)

Poster_IDM2024_Marasciulli.pdf

17:10 Constraining Light Dark Matter Particle properties with Cosmic Reservoirs

Dark Matter (DM) existence is a milestone of the cosmological standard model and, yet, its very nature discovery still remains a mystery. In this talk, I discuss a new way to probe properties of light-particle dark matter candidates which exploits the nature of the cosmic-ray (CR) transport inside starburst nuclei (SBNs). Indeed, SBNs are considered CR reservoirs, trapping them for ∼10^5 years up to ∼ PeVs energies, leading to copious production of gamma-rays and neutrinos. As a result, interactions between DM and protons might indelibly change CR transport in these galaxies, perturbing the gamma-rays and neutrino production. I will show that current gamma-ray observations pose strict limits on the elastic cross section down to σ_χp≃10^-34 cm^-2 for DM masses m_χ≤10^-3 MeV and that they have considerable room for improvement with the future gamma-ray measurements in the 0.1-10 TeV range from the Cherenkov Telescope Array.

Speaker: Antonio Ambrosone (Gran Sasso Science Institute (GSSI))

Light_Dark_Matter_Poster.pdf

17:10 Corrections on the electron g-2 from ultra light dark matter backgrounds

In this talk I will show how an ultra light dark matter background affects the electron g-2 value. The effect comes from an enhancement in the triangle diagram due to the high occupancy number of a boson field with a very low mass. The results are immediately used to put strong constraints on axion-electron couplings and dark photon kinetic mixing parameters, for masses below $10^{-15}$ eV.

Speaker: Ariel Arza (Nanjing Normal University)

17:10 COSINUS low-background experimental facility at LNGS

The Cryogenic Observatory for Signals seen in Next generation Underground Searches (COSINUS) is a direct dark matter search that utilizes sodium iodide (NaI) crystals as cryogenic calorimeters. Its primary objective is to provide a model-independent cross-check of the signal observed by the DAMA/LIBRA experiment. The cryogenic calorimeters will be operated in a dry dilution refrigerator positioned at the center of a water tank which functions both as a passive and active Cherenkov muon veto. In this contribution, we will introduce the active muon veto and elaborate on the main components of the low-background experimental infrastructure located at the Laboratori Nazionali del Gran Sasso in Italy.

Speaker: Kumrie Shera

2024_IDM_Kumrie_final.pdf

17:10 Dark Matter Subhalo Abundance in the Solar Neighborhood and Its Effect on Direct Detections

Lambda cold dark matter (ΛCDM) is widely considered as the standard model of the Big Bang cosmology that contains a postulated new particle called dark matter (DM), which makes up for 85% of the matter of the universe. However, DM has yet to be detected non gravitationally. One of the major ways of probing it is through direct detection experiments measuring the cross section of dark matter particles scattering off nuclei. Additionally, under ΛCDM, DM clumps up into halos and subhalos, potentially affecting our direct detection measurements if they happen to fly past the solar system and temporarily boost the local dark matter density. In this talk, I will give an estimation of the local abundance of low mass subhalos in the solar neighborhood and discuss the effect of their existence on direct detection. I will first introduce the local differential number density of subhalos, focusing on the dark low mass subhalos.I will then define the encounter cross section and further introduce the differential encounter rate for a subhalo to scatter off the Earth gravitationally that allows us to give an expected total number of yearly encounter events. Finally, I will discuss how such events are expected to affect the direct detection experiments. Although the rate is found to be quite small for the lifetime of direct detection experiments, this study inspires us to look for new ways to study the low mass subhalos, potentially through effects that can accumulate through years such as paleo detectors, and thus enable us to explore the lower end of the mass spectrum where the particle nature of DM plays a more important role.

Speaker: Xiuyuan Zhang

17:10 Data-driven identification of light signals from low-energy recoils in a LAr TPC using self-supervised machine learning

The Recoil Directionality (ReD) project, within the Global Argon Dark Matter Collaboration, aims to characterize the response of an argon double-phase Time Projection Chamber (LAr TPC) to low energy neutron-induced nuclear recoils (NR). Signals collected by Silicon Photomultipliers (SiPMs) in the LAr TPC are the prompt scintillation light in liquid (S1) and the delayed electroluminescence (S2) in gas. S2 signal is due to the electrons produced by ionization in liquid and drifted by an electric field towards the gas-liquid interface. For NRs in the few-keV range, the S1 signal is difficult to observe, thus making it crucial to measure effectively the ionization yield in argon.
A new data-driven technique involving self-supervised machine learning, in particular convolutional autoencoders (CAE), has been developed to improve the background rejection in S2-only events. A CAE is a feedforward neural network composed of two parts: an encoder, that compresses the information into a compact representation of reduced dimensionality, and a decoder, that aims to reconstruct the input from the reduced representation. In this analysis, the CAE is trained on a dataset of signals produced in the ReD TPC by neutrons and gamma-rays of a ^{252}Cf source, reducing each raw waveform (averaged over the SiPMs) into a 4-dimensional vector. The features of such compressed representation have been studied, developing a method to tag traces without pulses with a sensitivity, in the low-energy recoils region, comparable to the ReD conventional reconstruction.

Speaker: Ms Noemi Pino (Istituto Nazionale di Fisica Nucleare)

ReD_poster_NP_IDM2024.pdf

17:10 Density-functional theory description of xenon for dark matter-electron scattering in liquid xenon targets

We explore the effect of the interatomic interactions in the condensed phases of xenon on the dark matter-electron scattering process, with a focus on applications in liquid xenon detectors. We calculate the electronic structure of atomic, liquid and solid Xe using first-principles density functional theory (DFT), then compute material response functions for the dark matter-electron scattering process within an effective field theory framework. Finally, we use experimental data from XENON10 and XENON1T experiments to compare exclusion limits obtained for isolated atoms and for the condensed phase. Our results allow us to assess the impact of the interatomic interactions on dark matter-electron scattering in liquid xenon.

Speaker: Luca Marin (ETH Zurich)

17:10 Design and Benchmarking of the Underground Argon Cryogenics System for DarkSide-20k

DarkSide-20k (DS-20k) is a direct detection dark matter experiment and currently under construction at LNGS. It involves a total of ~100 t of low radioactivity argon from an underground source (UAr) in its inner detector, half of which serves as target in a dual-phase (liquid/gas) time projection chamber (TPC).
The cryogenics system for the UAr must provide the cooling necessary to fill the TPC at a defined pace by condensing gaseous UAr, and must maintain stable thermodynamic conditions over the course of the experiment's lifetime of >10 years, necessary for the science search. Furthermore, the UAr has to be efficiently and continuously purified from impurities and radon for optimal signal yield and background mitigation.
We have designed and constructed a highly efficient and powerful cryogenics system, capable of turning over the UAr inventory within ~40 days with a recirculation rate of 1000 slpm in a gas purification loop. At its core is a condenser using liquid nitrogen and a downstream heat exchanger cascade which provides a maximum combined cooling power of 8 kW.
We present the design of the cryogenics system in view of the requirements for DS-20k. We further detail on the results obtained during a testing campaign of the system's integral components with a dedicated benchmarking platform at CERN and LNGS.
We conclude with an outline of the impact of our findings on the finalisation process of the design and provide an outlook to its integration at LNGS.

Speaker: Kevin Thieme (University of Hawai'i)

Poster_IDM_2024_Kevin_Thieme.pdf

17:10 Development of SuperCDMS Silicon HVeV Detectors for Low Mass Dark Matter Searches and Studies of Low Energy Excess

The SuperCDMS-HVeV program has previously demonstrated competitive
sensitivities to electron-recoil [1] and nuclear-recoil [2] dark matter in the sub-
GeV mass range using voltage biased silicon crystals equipped with TES calorime-
ters. HVeV detectors have achieved excellent energy resolution through the
application of an electric field to the crystal that enables amplification via the
Neganov-Trofimov-Luke effect, allowing for eV-scale thresholds and enabling
low mass dark matter searches. However, recent direct-detection searches for
low mass dark matter including those from SuperCDMS [3], DAMIC [4], SEN-
SEI [5], CRESST [6], and EDELWEISS [7] have encountered an excess of events
at low-energy with unknown origin. As such, understanding the origin of these
events is crucial to the study dark matter. HVeV detectors are well-suited for
studies of this excess due to their excellent resolutions. New developments on
the original HVeV design seek to test hypotheses regarding the origin of low
energy events. In this poster, I will show two new iterations of HVeV detec-
tors each designed to test a different hypothesis. In the first new iteration of
HVeV detectors, an insulating layer is deposited between the crystal bulk and
the phonon sensors to reduce signal from the diffusion of charge carriers through
the crystal-sensor interface. The second iteration focuses on improving the po-
sition resolution of the HVeV detector in order to isolate stress-induced events
near the edge of the detector caused by mechanical clamping during operation.
References
[1] R. Agnese et al. “First Dark Matter Constraints from a SuperCDMS Single-
Charge Sensitive Detector”. In: Physical Review Letters 121.5 (Aug. 2018).
[2] M. F. Albakry et al. “Investigating the sources of low-energy events in a
SuperCDMS-HVeV detector”. In: Physical Review D 105.11 (June 2022).
[3] R. Agnese et al. “Low-mass dark matter search with CDMSlite”. In: Phys-
ical Review D 97.2 (Jan. 2018).
1
[4] I. Arnquist et al. “First Constraints from DAMIC-M on Sub-GeV Dark-
Matter Particles Interacting with Electrons”. In: Physical Review Letters
130.17 (Apr. 2023).
[5] Orr Abramoff et al. “SENSEI: Direct-Detection Constraints on Sub-GeV
Dark Matter from a Shallow Underground Run Using a Prototype Skipper
CCD”. In: Physical Review Letters 122.16 (Apr. 2019).
[6] A. H. Abdelhameed et al. “First results from the CRESST-III low-mass
dark matter program”. In: Physical Review D 100.10 (Nov. 2019).
[7] E. Armengaud et al. “Searching for low-mass dark matter particles with a
massive Ge bolometer operated above ground”. In: Physical Review D 99.8
(Apr. 2019).

Speaker: Kyle Kennard (Northwestern University)

17:10 DoubleTES detectors to investigate the CRESST low energy background: results from above-ground prototypes

The CRESST experiment utilises advanced cryogenic detectors constructed with different types of crystals equipped with Transition Edge Sensors (TESs) to measure signals of nuclear recoils induced by the scattering of dark matter particles in the detector.
In recent times, the sensitivity of low-mass direct dark matter searches has been limited by unknown low energy backgrounds close to the energy threshold of the experiments known as the low energy excess (LEE). In CRESST, this low energy background manifests itself as a steeply rising population of events below 200 eV.
A novel detector design named doubleTES using two identical TESs on the target crystal was studied to investigate the hypothesis that the events are sensor-related. We present the first results from two such modules, demonstrating their ability to differentiate between events originating from the crystal's bulk and those occurring in the sensor or in its close proximity.

Speaker: Francesca Pucci (Max Planck Institute for Physics)

doubleTES_poster_IDM.pdf

17:10 Electric Fields and their Effects in the LUX-ZEPLIN Experiment

Dual-phase noble liquid time projection chambers (TPCs) are at the forefront of direct dark matter detection experiments. Their functionality hinges on a meticulously designed homogeneous electric field structure defined by electrodes, material properties, and the relative permittivities of gas and liquid. These fields impact recombination processes within the target liquid (e.g xenon) and influence the drift path of ionisation electrons (S2 signal). This, in turn, affects both position reconstruction (combined with S1 signal) and the crucial discrimination between background-like electronic recoils and signal-like nuclear recoils. Furthermore, high voltage elements in these TPCs exhibit occasional anomalous electron or photon emission, a phenomenon attributed to field emission but lacking a deeper understanding. This talk delves into the multifaceted role of electric fields within the LUX-ZEPLIN (LZ) TPC. By employing data-driven and simulation techniques, we aim to illuminate charge transport mechanisms, energy-position reconstruction, and potential sources of this anomalous emission. This improved understanding will be crucial for designing and optimising future generations of dark matter detectors beyond LZ.

Speaker: Sparshita Dey (University of Oxford)

IDM 2024 Poster Final SD (3).png

17:10 Experiments on Collisions of Electrons or Protons with Hydrogen Atoms or Molecules Shed Light on the Possible Nature of Dark Matter

Analysis of atomic experiments related to the distribution of the linear momentum in the ground state of hydrogen atoms revealed a huge discrepancy: the ratio of the experimental and previous theoretical results was up to tens of thousands. This motivated a theoretical study resulting in the following discovery: for the states of zero angular momentum (S-states), the so-called “singular” solution of the Dirac equation outside the atomic proton, which was usually disregarded, can be matched without any problem with the regular solution inside the proton with the allowance for the experimental fact that the charge density inside protons has the maximum at r = 0. This solution eliminated the above huge discrepancy between the theoretical and experimental results (J. Phys. B: At. Mol. Opt. Phys. 34 (2001) 2235). Hydrogen atoms having only the S-states were called the Second Flavor of Hydrogen Atoms (SFHA) – by analogy with the flavors of quarks (Atoms 8 (2020) 33).
The 2nd experimental evidence of the existence of the SFHA was found by analyzing experiments on charge exchange of hydrogen atoms with incoming protons (Foundations 1 (2021) 265).
The 3rd experimental proof of the existence of the SFHA was obtained by analyzing experiments on the excitation of n=2 states of atomic hydrogen by the electron impact (Foundations 2 (2022) 541).
The 4th experimental proof of the existence of the SFHA was obtained by analyzing experiments on the excitation of the lowest triplet states of molecular hydrogen by the electron impact (Foundations 2 (2022) 697).
The primary property of the SFHA is that, since they have only the S-states, then according to the selection rules they cannot emit or absorb the electromagnetic radiation: they remain dark (except for the 21 cm spectral line). This and other properties of the SFHA led to important cosmological consequences.
First, there was a puzzling observation of the redshifted 21 cm spectral line from the early Universe where it was found that the absorption in this spectral line was about two times stronger than predicted by the standard cosmology (Nature 555 (2018) 67). The qualitative and quantitative explanation of this puzzle by using the SFHA made the latter the candidate for dark matter or a part of it (Research in Astron. and Astrophys. 20 (2020) 109).
Second, there were perplexing observations that the distribution of dark matter in the Universe is smoother than predicted by Einstein’s gravitation (Monthly Not. Roy. Astron. Soc. 505 (2021) 4626). However, it turned out that this puzzle can be also explained qualitatively and quantitatively by using the SFHA (Research in Astron. and Astrophys. 21 (2021) 241). This reinforced the status of the SFHA as the candidate for dark matter or a part of it.
The theoretical discovery of the SFHA was based on the standard Dirac equation of quantum mechanics without any change of physical laws.

Speaker: Eugene Oks

17:10 first results DAREDEVIL with GaAs mK calorimeter

The DAREDEVIL (DARk-mattEr-DEVIces-for-Low-energy-detection) is a new project aiming to
develop a novel class of detectors to study Dark Matter candidates with mass below 1 Gev/c^2. The
detection channel is DM-electron scattering, where the excitation energies of the electrons should
be matched to the transferred momenta. The only materials with energy gaps of eV or below are
special semiconductors, Dirac Semimetals, Weyl Semimetals, Scintillators. Such materials, already
explore from a theoretical point of view, will be implemented in a detector, has planned by the
DARDEVIL project. The first phase of the project aims at designing a novel class of gram-scale
detectors with meV threshold suitable for light DM-electron scattering detection. In order to achieve
the high performances needed for detecting such small energy depositions we will use these crystals
as absorbers in low temperature calorimeters with dual phonon and IR-photon readout.
In this contribution we present the very first results of a low temperature calorimeter based on GaAs
as the target crystal, operated at 15 mK coupled to a Neutron Transmutation Doped thermistor for
the phonon readout and facing a CdTeHg-based photon detector tuned to detect its IR scintillation
light.

Speakers: Andrea Melchiorre (Istituto Nazionale di Fisica Nucleare), Dr Dounia Helis (Istituto Nazionale di Fisica Nucleare)

Poster IDM2024-5.pdf

17:10 Hunting minimal dark matter quintuplet

This study investigates the sensitivity of the Cherenkov Telescope Array (CTA) and Fermi Large Area Telescope (Fermi-LAT) to dark matter (DM) annihilation in γ-ray lines. We focus on observations of the Galactic Center (GC), dwarf Spheroidal galaxies (dSphs), and galaxy clusters (GCls). Specifically, we compare the reach of the GC with that of dSphs, considering the poorly known putative core radius of the DM distribution. Surprisingly, we find that the currently best dSph candidates present a more promising target than the GC, especially for core radii ranging from one to a few kiloparsecs.

In addition to CTA prospects, we extend our analysis to incorporate Fermi-LAT data. Recent advancements in computations have highlighted the impact of Sommerfeld enhancement and bound-state formation on the annihilation cross section of Minimal Dark Matter (MDM) multiplets. Exploring this new paradigm, we examine Fermi-LAT data to assess its capability to detect or rule out a potential line arising from bound-state formation processes. Our findings reveal that the Fermi-LAT data effectively rules out the MDM 5plet at a significance level of 2σ, demonstrating the importance of considering enhanced cross sections and new annihilation signatures in the quest to unravel the mysteries of dark matter.

Speaker: Mohammad Aghaie Moghadam Ozbak (Istituto Nazionale di Fisica Nucleare)

17:10 Identifying Supermassive Dark Star Candidates in JWST Data

Early findings from the James Webb Space Telescope (JWST) defied the predictions of the 𝚲CDM model of cosmology. The major concern was the large overabundance of very massive, very high-redshift galaxies and quasars, at which time the universe was only a few hundred million years old. There are two major models for the nature of the first stars in the universe: Population III stars and Supermassive Dark Stars (SMDS). SMDS, in particular, offer a solution to the aforementioned paradoxes. Unlike Population III stars, SMDS are powered by dark matter annihilations, can grow to be a million times the mass of the sun, and shine a billion times brighter than the sun, and in fact as bright as an entire galaxy. At the end of their lives, SMDS would collapse directly to a black hole, and therefore could give rise to the first quasars observed. We have identified the first candidates for SMDS using the JWST Advanced Deep Extragalactic Survey (JADES): JADES-GS-z13-0, JADES-GS-z12-0, and JADES-GS-z11-0.

Speaker: Jillian Paulin

17:10 Intrinsic Background Characterisation of an Ultra-pure NaI Test Crystal for SABRE South

In this talk, I will present the characterisation results of an ultra-pure NaI(Tl) test crystal for the SABRE South experiment, using background counting and mass spectrometry techniques. I will describe the characterisation methods, including a detailed analysis on $^{238}$U and $^{232}$Th activities using a likelihood fit to the time distributions of $^{214}$Bi – $^{214}$Po, and $^{212}$Bi – $^{212}$Po coincidences, along with methods for determining the thallium dopant concentration. I will provide results for the light yield, alpha rates, cosmogenic activation, and intrinsic contaminant levels including $^{238}$U, $^{232}$Th and $^{40}$K.

The Sodium Iodide with Active Background Rejection (SABRE) dark matter experiment aims to provide a model independent test of the DAMA/LIBRA annual modulation. SABRE will consist of dual detectors in the Northern and Southern Hemispheres with ultra-pure NaI(Tl) crystals, whose purity is planned to rival that of DAMA/LIBRA. This talk reports on the results for a 3.7 kg crystal made with Merck’s AstroGrade quality powder. The crystal, called NaI-035, was produced by RMD, based in Boston, USA. This crystal has low intrinsic background contaminant levels, and demonstrates that viable NaI(Tl) crystals can be grown to meet SABRE requirements.

Speaker: Ferdovs Dastgiri

17:10 Low-frequency noise classification using Machine Learning for the SuperCDMS experiment

The SuperCDMS experiment uses semiconductor crystal detectors operated at cryogenic temperatures to search for low-mass dark matter. Vibrations observed during the SuperCDMS Soudan experiment generated broadband low-frequency (LF) noise, which due to its similarity in the pulse shape to the low-energy signal events are difficult to remove at low-energies. In the final low ionization threshold analysis, a strong event selection criterion was applied to remove LF noise events which raised the analysis threshold and thus reduced the sensitivity of the experiment to low-mass dark matter. An LF noise selection criterion using machine learning is currently being studied. Under investigation is a convolutional neural network that yields better signal purity while also retaining signal efficiency. This talk discusses the preliminary results of the machine learning-based classification of LF noise.

Speaker: Sukeerthi Dharani (KIT / UHH)

17:10 Manifesting hidden dynamics of a sub-component dark matter

A distinctive cosmological dynamics of a sub-component dark matter will be discussed. The thermal evolution of the sub-component is significantly affected by the sizable self-scattering and the required annihilation cross section of the sub-component sharply increases as we consider a smaller relative abundance fraction among the dark-matter species. Therefore, contrary to a naive expectation, it can be easier to detect the sub-component with smaller abundance fractions in direct/indirect-detection experiments and cosmological observations.

Speaker: Seodong Shin (Jeonbuk National University)

IDM2024-Poster-Shin.pdf

17:10 Many-Body Atomic Response for Light Dark Matter-Electron Interactions and Low-Energy Solar Neutrino Detection

Electronic recoil signals are the main observables in direct searches of light dark matter (LDM) and detection of low energy neutrinos. In the energy deposition range of 10 (80) eV to 1 keV for xenon (germanium) detectors, the atomic effects are known to be important. In this talk, I will present a database of response functions for LDM-ionized xenon and germanium, based on relativistic random phase approximation (RRPA), which is a genuinely many-body approach.

For ionization by solar neutrinos, we push the energy range beyond the 30 keV limit of our previous work with RRPA [1] up to 150 keV. The comparison with other simplified methods such as plane-wave approximation and free-electron approximation with stepping will also be discussed.

[1] Jiunn-Wei Chen, Hsin-Chang Chi, C.-P. Liu, and Chih-Pan Wu, Phys. Lett. B 774 (2017) 656.

Speaker: Chih-Pan Wu (National Dong Hwa University)

17:10 Molecular sieve vacuum swing adsorption purification and radon reduction system for gaseous dark matter and rare-event detectors

In the field of directional dark matter experiments, SF₆ has emerged as an ideal target gas. A critical challenge with this gas, and with other proposed gases, is the effective removal of contaminant gases. This includes radon which produces unwanted background events, but also common pollutants such as water, oxygen, and nitrogen, which can capture ionisation electrons, resulting in loss of detector gas gain over time. We present here a novel molecular sieve (MS) based gas recycling system for the simultaneous removal of both radon and common pollutants from SF₆. The apparatus has the additional benefit of minimising gas required in experiments and utilises a Vacuum Swing Adsorption (VSA) technique for continuous, long-term operation. The gas system's capabilities were tested with a 100 L low-pressure SF₆ Time Projection Chamber (TPC) detector. For the first time, we present a newly developed low-radioactive MS type 5 Å. This material was found to emanate radon at 98% less per radon captured compared to commercial counterparts, the lowest known MS emanation at the time of writing. Consequently, the radon activity in the TPC detector was reduced, with an upper limit of less than 7.2 mBq at a 95% confidence level (C.L.). Incorporation of MS types 3 Å and 4 Å to absorb common pollutants was found successfully to mitigate against gain deterioration while recycling the target gas.

Speaker: Robert Renz Marcelo Gregorio (Queen Mary University London)

17:10 NaI-remoTES: Cryogenic detectors with delicate absorbers

COSINUS (Cryogenic Observatory for SIgnals seen in Next generation Underground Searches) operates sodium iodide (NaI) as cryogenic scintillating calorimeter using transition edge sensors (TES) at temperatures around 15 mK. TES are commonly used in cryogenic calorimeters for their excellent energy resolution. However, due to the various manufacturing steps involved, the choice of absorbers does not include soft and hygroscopic crystals such as NaI.

To overcome this challenge COSINUS developed the remoTES design, a novel method to equip a wide range of absorbers with a TES. In this design, the TES is deposited on a separate wafer and thermally connected to the absorber via a gold link which consists of a bond wire and a gold pad for phonon collection. The remoTES was tested on Si, TeO2, and NaI and reached baseline resolutions below 100 eV, 200 eV, and 400 eV respectively. This talk provides a description of the remoTES design and the current status of optimization studies on NaI.

Speaker: Moritz Kellermann (Max Planck Institute for Physics)

2024_Kellermann_IDM_poster_pdf.pdf

17:10 Negative Ion Gridpix based High resolution TPC (NIGHT) detector

Time projection chambers (TPC) operating with a negative ion gas have the potential to be used in directional dark matter searches. The proof of concept detector, NIGHT, is a TPC with a GridPix readout, which in turn consists of a Timepix ASIC with an integrated amplification stage called InGrid. It has an active area of 1.4cmx1.4cm and a drift length of 3cm.

The detector will be operated with a mixture of He and the negative ion gas SF6 at different ratios and pressures and the results will be compared with the electron drift gases. With this study, we aim to understand not only the properties of SF6 but also the benefits of the pixelated detector to be used in directional dark matter searches.

In this poster, the NIGHT detector will be presented regarding its principles, design and preliminary results.

Speaker: Saime Gürbüz (University of Bonn)

gurbuz-night-idm2024_poster.pdf

17:10 No-go for freeze-in DM in right-handed neutrino extended MSSM (not final).

We investigate the possibility of saturating the relic density bound with light higgsinos. When the minimal supersymmetric Standard Model is extended with right-handed neutrino superfields and the seesaw scale is very low, right sneutrinos can be produced via the freeze-in mechanism. In such a case we can have essentially two independent sources for dark matter, the traditional freeze-out of higgsinos and the freeze-in of right-handed sneutrinos. The heavier of these two will decay to the lighter species with a delay. We have ruled out such a scenario for all seesaw models as the lifetime of sterile neutrino, produced via Dodelson-Widrow mechanism, exceeds the age of the universe and will contribute to the relic density.

Speaker: Mr Tushar Gupta (Helsinki Institute of Physics, University of Helsinki)

146_poster_tushar.pdf

17:10 Not so inelastic Dark Matter

Models of inelastic (or pseudo-Dirac) dark matter commonly assume an accidental symmetry between the left-handed and right-handed mass terms in order to suppress diagonal couplings. Here we point out that this symmetry is unnecessary, because for Majorana fermions the diagonal couplings are in fact not strongly constrained. Removing the requirement of such an accidental symmetry in fact relaxes the relic density constraint, because additional annihilation modes can contribute, leading to larger viable parameter space. We discuss how the sensitivity of searches for both long-lived particles and missing energy signatures is modified in such a set-up, and explore the relevance of events with two long-lived particles.

Speaker: Giovani Dalla Valle Garcia (IAP - KIT)

niDM poster - A0.pdf

17:10 Numerical simulations of 3D recoil responses of Solar B-8 neutrinos in directional direct Dark Matter detectors

In this talk, we will present our numerical simulation results of 3D recoil distributions of coherent elastic Solar B-8 neutrino-nucleus scattering events, which could be observed by future directional direct Dark Matter detectors. These results are achieved by our 3D Monte Carlo scattering-by-scattering simulation package, built originally for 3D elastic WIMP-nucleus scattering events. Dependence on detector material, laboratory location as well as annual/diurnal observation period will be discussed.

Speaker: Dr Chung-Lin Shan

CEnuNS-NR_ang-IDM2024.pdf

17:10 Optimisation of fast likelihood functions for dark matter and rare event searches

Flamedisx provides a unique method of calculating likelihoods for rare event searches in liquid xenon time-projection chambers, like LUX-ZEPLIN, without the need for exhaustive monte-carlo simulations. Rather than random sampling of underlying parameters, flamedisx evaluates the range of possible parameters that could have significantly contributed to an observed event allowing for faster evaluation of more observables and shape varying parameters. This is represented in a large tensor calculation optimised with differential programming in TensorFlow. The implementation of Noble Element Simulation Technique (NEST) Xe response models in flamedisx, necessary to model light and charge response of Xe in a way consistent with other experiments, resulted in a more complex model which significantly increased memory consumption and execution time. Various optimisations made inference with more observables possible but the memory and time issues restrained possibilities with shape varying parameters. This work resolves the complexity of the NEST models through manipulation of the tensors and gives examples of where introducing shape varying parameters can improve analyses.

Speaker: Joshua Green (University of Oxford / LZ)

JRG_FlameNEST_IDM2024.pdf

17:10 Optimisation of gas composition and amplification stage for the CYGNO/INITIUM experiment

CYGNO is an international collaboration working on the development of a directional detector whose main goal is the direct detection of rare events, such as Dark Matter (DM) in the mass range below few tens of GeV/c2, by means of a gaseous detector. It exploits the expected directional anisotropy of the DM candidates by measuring the orientation of the track, in addition to the energy released in the active medium. It will consist in a Time Projection Chamber (TPC) filled with a He:CF4 gas mixture equipped with an amplification stage composed of a triple Gas Electron Multiplier (GEM) structure. Given the scintillating properties of the gas, the readout is optical, based on sCMOS cameras and fast photomultiplier tubes. A demonstrator of 0.4 cubic metre is under development and will be hosted at Laboratori Nazionali del Gran Sasso in 2024.
We will illustrate the ongoing activities of R&D whose goal is to improve the sensitivity and the performances of the future detector. Such studies include the optimisation of the gas mixture composition, with the possibility of adding hydrogen-rich compounds to enhance the DM sensitivity in the low mass range down to 500 MeV/c2, or of inserting electronegative molecules to exploit negative ion drift and obtain better tracking capabilities. Furthermore, the possibility of introducing a strong electric field below the GEM amplification structure to amplify the light output of the detector will be discussed.

Speaker: Giorgio Dho (Istituto Nazionale di Fisica Nucleare)

Poster_Dho.pdf

17:10 Optimising recoil imaging detectors for extraterrestrial particles

The experimental search for WIMP-like dark matter remains inconclusive.
As these experiments grow in size and more of the available parameter space is investigated and excluded, it is necessary to plan ahead to circumvent the looming neutrino fog, which constitutes a near-irreducible background for an experiment sensitive to only recoil energy.

The direction of the incoming flux of dark matter is unique, hence it pro-
vides a smoking-gun signal to unambiguously claim discovery. Accessing this information would then make it possible to discern between dark matter and other sources.

To accurately determine the origin of an incoming particle, a directional
detector must be capable of resolving the spatial dimensions of the ionisation tracks, for example micro-pattern gas detectors (MPGDs), which can be used as the readouts for gas time projection chamber (TPC)-based experiments such as CYGNUS.

It is, then, vital to carefully consider how the sensitivity will depend on the geometry, location, alignment and orientation of the experiment. Our aim is to analyse these parameters for different sources of particles, ultimately devising a set of clear guidelines to maximise the performance of any 3D recoil imaging detector.

Speaker: Chiara Lisotti (University of Sydney)

IDM poster- Lisotti-Finale.pdf

17:10 Optimum Filter Analysis in CRESST

The Cryogenic Rare Event Search with Superconducting Thermometers (CRESST) experiment aims for the direct detection of dark matter. A low energy threshold and a high resolution at low energies are critical for exploring parameter space in the current low-mass DM search. Together with hardware modifications, a new strategy based on the optimum filter method, which optimises the signal-to-noise ratio, is used in the most recent CRESST analysis to improve the energy threshold. This allows the experiment to be among the leading ones in probing sub-GeV DM masses. In this work, additional digital filtering and calibration techniques have been tested for performance and improvement of the optimal filter method.

Speaker: Lena Meyer

17:10 Positron annihilation in flight as a probe of new physics

A steady production of positrons in the Milky Way is evidenced by the long-standing observations of a diffuse $511$ keV $\gamma$ ray line from electron-positron annihilation. One consideration that is usually ignored is that the interaction of positrons with the interstellar medium produces not only a line, but also a continuum emission (so called) in-flight positron annihilation.
We use, for the first time, the $\gamma$-ray emission from in-flight positron annihilation as a powerful observable for constraining high-energy positron production from electrophilic Feebly Interacting Particles, demonstrating that in-flight annihilation (IA) emission can significantly constrain these particles based on diffuse $\gamma$ ray observations. When applied to the case of MeV-scale sterile neutrinos, we set the most stringent constraint, excluding $|U_{\tau4}|^{2} \gtrsim 5\times 10^{-13}$ for sterile neutrinos mixed with the tau flavor. These constraints are more than an order of magnitude more stringent than previous limits. We remark that our approach is applicable to a host of exotic positron sources such as primordial black holes, sub-GeV dark matter, dark photons and axion-like particles as well.

Speaker: Pedro De la Torre Luque (Institute of theoretical physics (IFT))

17:10 Potential of RES-NOVA as a Dark Matter observatory

The quest to understand dark matter (DM) continues to be a driving force in astrophysics and particle physics. This talk discusses the potential of the RES-NOVA project, envisioned for detecting astrophysical neutrinos via Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS), to also serve as a DM observatory. Leveraging the array of cryogenic detectors made from archaeological Pb, known for its ultra-high radiopurity, RES-NOVA is uniquely positioned to detect both neutrino and DM interactions via nuclear recoils. The use of Pb significantly enhances the coherent elastic neutrino-nucleus scattering cross-section, making it an ideal candidate for astrophysical phenomena investigation. By extending the operational principles and sensitivity of CE$\nu$NS-based detectors, RES-NOVA may also be capable of observing DM particles from our galactic halo. The theoretical implications for such dual-use in RES-NOVA, the detector design, sensitivity, and a preliminary background model aimed at identifying DM candidate signals, are described.

Speaker: Luca Pattavina (UNIMIB & INFN)

17:10 Quantum entanglement of ions for light dark matter detection

A detection scheme is explored for light dark matter, such as axion dark matter or dark photon dark matter, using a Paul ion trap system. We first demonstrate that a qubit, constructed from the ground and first excited states of vibrational modes of ions in a Paul trap, can serve as an effective sensor for weak electric fields due to its resonant excitation. As a consequence, a Paul ion trap allows us to search for weak electric fields induced by light dark matter with masses around the neV range. Furthermore, we illustrate that an entangled qubit system involving $N$ ions can enhance the excitation rate by a factor of $N^2$. The sensitivities of the Paul ion trap system to axion-photon coupling and gauge kinetic mixing can reach previously unexplored parameter space.

Speaker: Wakutaka Nakano (KEK)

Nakano.pdf

17:10 Search for dark matter subhalos among Fermi-LAT sources in presence of dataset shift

Main contribution:

This work aims to identify a signal from dark matter among gamma-ray sources detected by the Fermi Large Area Telescope using machine learning techniques.

For the first time, we write the full likelihood for a model of the unassociated gamma-ray sources, including a model for extragalactic as well as galactic gamma-ray sources and dark matter annihilating through the $b \overline{b}$ channel.

This will enable us to draw bounds on the annihilation cross-section of dark matter by employing a technique never adopted before (to the best of our knowledge), opening a new way to search for dark matter with considerable potential for further refinement and improvement.
As a corollary result, we achieve a principled probabilistic classification of the unassociated gamma-ray sources, making them no more unassociated, at least from a probabilistic point of view.

Physics background:

If dark matter particles annihilate and produce standard model particles, those particles may interact and produce gamma rays. Due to their high-energy nature, gamma rays suffer much less from absorption effects due to the interstellar medium as well as deviation in their trajectory due to electromagnetic fields. These properties paired with a comparatively lower astrophysical background point at gamma rays as a prime target of interest for Dark Matter indirect detection.

Among the gamma-ray sources identified by the Fermi Large Area Telescope, approximately one-third remain without a clear astrophysical association. While still unassociated, we expect most of them to be of astrophysical origin. Nonetheless, a small fraction of them could be dark matter sub-halos, whose signal we aim to disentangle.

In general, it is possible to study a gamma-ray source through several means. It is possible to study gamma-ray sources by themselves by analyzing their energy spectrum and/or variability index. In alternative, one can employ multiwavelength approaches, by comparing a gamma-ray signal with its counterparts in the entirety of the electromagnetic spectrum.

An accurate study for extragalactic gamma-ray sources is generally possible and it leads to a clear association for approximately 90% of the detected sources.
On the other hand, approximately 50% of the sources closer to the galactic plane remain unassociated. This is in part due to the higher density of gamma rays coming from the galactic plane which makes resolving and characterizing individual sources more difficult. Furthermore, the presence of absorption effects acting on radiation less energetic than soft X-rays makes it hard if not impossible to employ multi-wavelength approaches to classify these already elusive gamma-ray sources.

In this work, we focus our attention on the energy spectrum of the unassociated gamma-ray sources, as different classes of sources follow different energy spectrum distributions.
We parametrize the energy spectrum of the gamma-ray sources measured by Fermi-LAT using a LogParabola fitting formula with 3 free parameters: an overall normalization, the spectral index, and the curvature parameter.
Studying the distribution for these parameters, we will identify different regions in the parameter space corresponding to the distinct astrophysical and DM components. This would potentially enable us to disentangle a signal from Dark Matter or, as is the present case, draw bounds on the DM annihilation cross-section in its absence.

Speaker: Aurelio Amerio (IFIC, University of Valencia, CSIC)

Poster Amerio Aurelio - IDM2024

17:10 Search for spin dependent exotic interactions using mechanical sensors and magnetic structures

Extensions to the Standard Model often introduce new bosons that can mediate exotic spin-dependent interactions. The hypothetical bosons, including axions, majorons, dark photon, Z’ bosons etc., may be candidates for dark matter particles. Searching for such spin-dependent interactions can extract important information about the bosons, such as mass and coupling strength with the Standard Model particles, thus providing an indirect approach for exploring dark matter particles. Here I will present the experiments we are conducting to search for spin- and velocity- dependent exotic interactions with mechanical sensors. These interactions may be mediated by spin-1 bosons, such as the generic Z’ boson. Mechanical sensors are used to measure the force between a nucleon source and a spin-polarized electron source (magnetic structure). To distinguish between the exotic interaction and the electromagnetic forces, the spin-polarized electron sources are specially designed to generate space-modulated exotic interaction signals with a constant electromagnetic force background. Based on the preliminary experimental data, stronger constrains on the exotic interaction are given.

Speaker: Prof. Pengshun Luo (Huazhong University of Science and Technology, China)

IDM poster_Luops_V4.pdf

17:10 Searching for spin-dependent exotic interactions with ferromagnetic microsphere-cantilever probes

Spin-dependent exotic interactions may occur between two fermions through exchanging of hypothetical bosons, such as axions, Majorons, familons, Z’ bosons, some of which may be candidates for dark matter particles. These interactions can be measured at the tabletop scale with high precision experiments, providing indirect experimental information about the mediators. Here, we report an experimental search for two exotic interactions, denoted V12+13 and V9+10, in the micrometer range using frequency-modulation atomic force microscopy. A cantilever is employed as a weak force sensor to measure the exotic interactions between nucleons in a density-modulated structure and spin-polarized electrons in a ferromagnetic microsphere glued at the end of the cantilever. During data acquisition, the ferromagnetic microsphere probe is driven to vibrate at its resonance frequency. When the cantilever is subjected to the V12+13 or V9+10 interaction, its amplitude or resonant frequency changes. If the exotic interactions exist, the probe will experience periodically varying forces as it passed over the masses of Au and SiO2 in the density-modulated structure, which results in periodic changes in the vibration amplitude or resonance frequency of the cantilever. Maps of the amplitude and resonance frequency are recorded simultaneously by scanning over the surface of the nucleon source at a certain distance. The maximum likelihood estimation method is used to analyze the data. The experiment sets a new limit on the V12+13 interaction in the interaction range from 0.7 um to 5 um, the coupling constant g_A^e g_V^N at λ = 1.3 um should not exceed 4.8×10^(-15). The limit on the V9+10 interaction is also given in the interaction range from 0.2 um to 40 um, the coupling constant (g_s^N g_p^e)⁄ℏc should be less than 5.5×10^(-17) at λ = 4.0 um.

Speaker: Rui Luo (Huazhong University of Science and Technology, china)

17:10 Sourcing axions in the magnetospheres of neutron stars

Neutron stars can host strong electromagnetic fields deep in their magnetospheres capable of sourcing axions. Low mass axions are produced relativistically and can resonantly convert into radio photons as they escape the magnetosphere. For heavier axions an increasing fraction will instead end up populating a dense cloud of bound states around the parent neutron star. In this talk I will discuss the fundamental physics driving both axion production and conversion in these scenarios, followed by an end-to-end analysis pipeline that facilitates an accurate description of the prospective radio flux. This is finally used to derive some of the strongest constraints to date on the axion-photon coupling, as well as projections that show there is considerable room left for future improvement.

Speaker: Dion Noordhuis (University of Amsterdam)

17:10 Status of fermionic sub-GeV dark matter

Models of Sub-GeV dark matter coupled to a dark photon with kinetic mixing feature a rich phenomenology. They are thus constrained by a number of laboratory, astrophysical and cosmological observations. The biggest obstacle for fermionic DM particles to make up all of the observed DM comes from the strong constraints placed by the CMB and X-ray emission on DM annihilation. This can be overcome by introducing a particle-antiparticle asymmetry. The viability of these models then depends on the delicate interplay between different constraints and the model features. I will present the results of global fits of (a)symmetric fermionic DM and conclude with projections of future experiments.

Speaker: Sri Sankari alias Sowmiya Balan (Karlsruhe Institute of Technology)

SubGeV_Poster.pdf

17:10 Studies of radioactive background from environment for a potential LXe dark matter experiment at Boulby

Rare event searches, such as those targeting dark matter interactions and neutrinoless double beta decay (0νββ), face challenges from gamma-rays originating in rock, contributing to electron recoil background. This report presents a dual investigation: measurements of natural radioactivity in rock samples from Boulby Mine and a simulation assessing shielding thickness for a future detector. The measurements provide data for normalising conditions in prospective experiments at Boulby. The simulation studies the effectiveness of water shielding around a detector, focusing on the Weakly Interacting Massive Particle (WIMP) energy range (0 – 20 keV) and the energy range near the 0νββ Q-value (2.458 MeV).

The study design features a simplified xenon-based detector with a 70-tonne active volume, encompassed by veto systems and water shielding. Our findings indicate that gamma-ray background is unlikely to persist through analysis cuts in the WIMP energy range. However, for 0νββ decay signal searches, adjustments will be required; the sensitivity of a next-generation detector demands a background of < 1 event per 10 years, necessitating a reduction in the fiducial volume of the detector.

Speaker: Jemima Tranter (University of Sheffield)

IDM2024_poster.pdf

17:10 The DarkSide-20k Photo Detection Unit packaging process flow in NOA

DarkSide-20k is a dual-phase liquid argon time projection chamber (LAr-TPC) detector for the direct detection of dark matter (DM) particles that is under construction in Hall C of the Laboratori Nazionali Del Gran Sasso (Italy).
Light detection represents a critical and challenging aspect of this detector. The light collection is based on the novel FBK NUV-HD Cryo silicon photomultiplier (SiPM) devices. SiPMs are extracted from 1400 8-inch production wafers, each consisting of 268 dies, and bonded into 528 photodetection units (PDUs) in a new ISO-6 400 m^2 clean room packaging facility built at INFN LNGS. This talk will present a detailed account of the process flow for the production of PDUs. It will commence with an overview of the SiPMs wafer testing and dicing procedures, before progressing to the SiPMs bonding and examination of the final assembly stage. Additionally, the presentation will provide an insight into the software and database framework utilized for the analysis and storage of data acquired throughout the entire process chain.

Speaker: Paolo Salomone (Istituto Nazionale di Fisica Nucleare)

17:10 The demonstrator of BULLKID-DM: Commissioning and first results

BULLKID-DM is a novel experiment to search for WIMP-like dark matter with mass around 1 GeV/c^2.
The detector consists of an array of silicon targets sensed by multiplexed Kinetic Inductance Detectors (KIDs).
The detection principle consists in sensing athermal phonons produced in the crystal by particle interactions.
BULLKID-DM will deploy 600 g of active silicon target, segmented in more than 2500 detector units in order to allow background identification and rejection via single-site/multi-site analysis.

The project is currently operating on surface a demonstrator array consisting of 180 detector units of 0.35 g each for a total active mass of 60 g.
In this poster we present the construction, the operation and the data analysis of this array.

Speaker: Daniele Delicato (Istituto Nazionale di Fisica Nucleare)

Poster_IDM_v04.pdf

17:10 The detection of spin- and velocity-dependent exotic interaction at the micrometer range

Theories beyond the Standard Model usually predict the existence of new particles and interactions. Assuming that there are new bosons with spin of 0 or spin of 1, the exchange of these bosons can give rise to sixteen types of interactions. Here we present the experimental progress in the detection of one of them, the spin- and velocity-dependent interaction, at the micrometer range using a cantilever. A home-built scanning probe microscope is used to detect the interaction between polarized electrons in a periodic FeCo film structure (spin-modulated structure) and unpolarized nucleons in a gold sphere glued on the cantilever. During data acquisition, the spin-modulated structure is driven to vibrate in a sinusoidal form. If the exotic interaction exists, the gold sphere will sense a periodically time-varying force produced by the spin-modulated structure. The displacement of the cantilever is measured in real-time using a fiber interferometer. The exotic interaction is modulated to the 10th harmonics of the driving frequency, which helps to separate the spurious signals from the signal of interest in the frequency domain. Since the new interaction is proportional to the relative velocity between the two objects, the driving frequency is optimized to 18.85 Hz to increase the effect of the new interaction and minimize the vibration disturbance. The noise floor of the sensor is about ~20 fN/√Hz at 188.5Hz. It is expected that the limit on the spin- and velocity-dependent interaction will be improved by one order of magnitude compared to the previous constraint.

Speaker: Sumin Li (Huazhong University of Science and Technology, Wuhan, China)

17:10 The effect of the LMC on non standard interactions for future dark matter direct detection experiments

Previous studies have shown the effect of the Large Magellanic Cloud (LMC) on the local speed distribution of the dark matter particles. Since it dominates the high speed tail of the distribution and the gravitational interaction also boosts the solar neighbourhood dark matter particles to higher velocities, such an effect has an impact on direct detection searches. In this talk, I will discuss the impact of the LMC on the expected signals in different future direct detection experiments taking into account not only the standard spin-independent (dependent) signal but different dark matter - nucleon interaction types following the Non-Relativistic Effective Field Theory approach. Furthermore, I will discuss how the LMC affects the results in the case of inelastic dark matter.

Speaker: Javier Reynoso Cordova (University of Alberta)

17:10 The Inner Dark Matter Distribution in Hydrodynamic Simulations

Understanding the dark matter distribution within a few kpc of the galactic center of the Milky Way is essential in estimating the dark matter content of the galaxy for indirect detection experiments, as well as understanding the particle nature of dark matter through the density profile in the Milky Way’s core. Although it is difficult to accurately measure the inner stellar distribution in order to infer the dark matter distribution close to the galactic center, we can gain insight from cosmological simulations. However, the implementation of the baryonic physics in cosmological simulations varies between suites, making it more challenging to draw conclusions about our own Galaxy. In particular, these implementations are quite opaque at best, and for some simulation suites not publicly available. In this talk, I will discuss how we characterized the dark matter density profile in FIRE-2, Auriga, Vintergatan, and Illustris TNG50 using the adiabatic contraction algorithm from [1] to predict the dark matter density profile in the hydrodynamic simulations. I will show that Auriga, Vintergatan, and Illustris TNG50 can be well described by adiabatic contraction, while the stellar feedback in FIRE-2 dominates over the effects of the baryonic contraction. I will close by showing the dark matter annihilation/decay rates in simulations as well as predictions for the Milky Way’s inner dark matter density profile and annihilation flux using observations of the stellar density profile.

[1] Oleg Y. Gnedin et al 2004 ApJ 616 16 (2004)

Speaker: Abd El Aziz Hussein (MIT)

IDM_poster.pdf

17:10 Topological Portal to the Dark Sector

We propose a topological portal between quantum chromodynamics (QCD) and a dark QCD-like sector. Such a portal is present only for a unique coset structure after QCD confinement and it connects three QCD to two dark pions. When gauged, it is the leading portal between the two sectors, providing an elegant self-consistent scenario of light thermal inelastic dark matter. The inherent antisymmetrization due to a Wess–Zumino–Witten-like effective interaction leads to diminished annihilations at later times and suppressed direct detection. However, novel collider signatures offer tremendous prospects for discovery at Belle II.

A related preprint can be found at: https://arxiv.org/pdf/2401.09528

Speaker: Nudzeim Selimovic (INFN Padova)

17:10 Towards axionic dark matter measurements with CASPEr-gradient

Axions and axion-like particles (ALPs) are well-motivated dark matter candidates which are collectively referred to as ALPs. The Cosmic Axion Spin Precession Experiments (CASPEr) [1] is an international research program searching for ALPs using nuclear magnetic resonance (NMR) techniques. CASPEr-gradient low-field in Mainz probes the hypothetical coupling of the gradient of the ALP field to nuclear spins [2] for Compton frequencies between $1\,\mathrm{kHz}$ and $4.2\,\mathrm{MHz}$ using a tunable superconducting magnet and a detection system based on superconducting quantum interference devices (SQUIDs). To probe higher frequencies in the range $70$ to $600\,\mathrm{MHz}$ CASPEr-gradient high-field was recently installed and is currently operating in Mainz. The setups and recent experimental efforts of CASPEr-gradient are presented including a demonstration measurement with thermally-polarized sample to search for ALPs at a Compton frequency of $1.3\,\mathrm{MHz}$.

[1] D. F. J. Kimball et al. ``Overview of the Cosmic Axion Spin Precession Experiment (CASPEr)''. In: Microwave Cavities and Detectors for Axion Research. Cham: Springer International Publishing, 2020, pp. 105-121. ISBN: 978-3-030-43761-9

[2] Graham, Peter W., and Surjeet Rajendran. ``New observables for direct detection of axion dark matter.'' Physical Review D 88.3 (2013): 035023. DOI: 10.1103/PhysRevD.88.035023.

Speaker: Olympia Maliaka

maliaka.IDMposter2024.pdf

17:10 What blazar jets tell us about axion-like particles

Prompt emissions from TeV blazars pair produce on the extragalactic background light and the resulting electrons and positrons then undergo inverse Compton scattering, giving rise to secondary gamma-rays. The non-observation of such reprocessed emission implies a suppression of cascades from TeV blazars. In addition to the deflection of the electron-positron pairs off the line of sight by the extragalactic magnetic field, plasma instabilities can transport some of the energy away from the pair beam and into the intergalactic medium. In this talk, I will discuss how certain dark matter candidates such as axion-like particles can affect the evolution of blazar jets and vice versa.

Speaker: Oindrila Ghosh (Stockholm University & the Oskar Klein Centre)

17:10 XENONnT physics-driven 6D Surface Background Model

The direct dark matter experiment XENONnT utilizes a dual-phase TPC with an active target of approximately 5.9 t of liquid xenon.
To optimize the detection of scintillation light, the TPC is enclosed by PTFE panels refined with a diamond-tip process.
These panels, in direct contact with the liquid xenon, can introduce a radiation background due to the long-lived Pb210 contaminant, which originates from the panels exposure to radon in the air.
This surface background mostly accounting for electrons and gammas generated in the Pb210 decay chain exhibits a different behavior with respect to the other electronic-recoil backgrounds.
Indeed, suffering from a S2 signal loss, these events present a lower ratio of ionization to scintillation signals, dangerously leaking into the nuclear recoil band, where the WIMP signal is searched.
The conventional method exploited to mitigate the impact of this background combines a geometrical fiducial volume cut with a data-driven model developed on unblinded side-bands.
The study reported here aims to assess the feasibility of a physics-driven surface background model with the goal of utilizing a more reliable model for future WIMP searches, and potentially expanding the fiducial volume to increase experimental exposure.

Speaker: Cecilia Ferrari (Istituto Nazionale di Fisica Nucleare)

IDM24.pdf

17:30 → 19:30 Social event: guided tour of the city of L'Aquila

L'Aquila-visit.pdf

Thursday, 11 July

09:00 → 10:30 Plenary

Convener: Giulia Pagliaroli (Istituto Nazionale di Fisica Nucleare)

09:00 The future of directional searches

I will review the motivation for pursuing the direction-sensitive detection of dark matter, e.g. for confirming the galactic origin of a signal, or for exploring into the neutrino fog. I will then review experimental methods that can perform such measurements across the dark matter model landscape, and highlight recent progress in the field.

Speaker: Ciaran O'Hare (University of Sydney)

d.pdf

09:30 Indirect Searches for Dark Matter

I will review the status of indirect searches for dark matter, including those using cosmic ray antimatter, gamma rays, and photons at other wavelengths. I will also summarize several of the anomalies and excesses that have been reported in the literature, and discuss ways in which the origins of these would-be signals for dark matter could be clarified.

Speaker: Dan Hooper (Fermilab/University of Chicago)

IDM-2024-Indirect.pdf

10:00 Search of Dark Matter in Cosmic Ray Anti-Matter

Antiparticles are a natural component of cosmic radiation since they are produced in the interaction between cosmic rays and interstellar matter. Cosmic-ray positrons and antiprotons were first observed in pioneering experiments in the sixties and seventies, respectively. Since their first observation, it has been apparent that cosmic-ray antimatter can shed light on the nature of dark matter.
Measurements of cosmic-ray antiparticle spectra have shown intriguing features that may indicate contributions from the annihilation or decay of dark matter particles. However, uncertainties about the secondary production of antiprotons, by the interaction of cosmic rays with interstellar matter, and their propagation in the Galaxy and the heliosphere are affecting a comprehensive understanding of their origin. Heavier cosmic-ray antinuclei, such as antideuterons and antihelium, are also predicted to be produced as secondaries. However, their spectra, especially at energies below a few GeV/n, are expected to be orders of magnitude lower than those of antideuterons and antihelium produced by plausible models of dark matter annihilation or decay.
Several experiments, equipped with state-of-the-art detectors, have recently presented, or are going to present, new results on the antimatter component of cosmic radiation with a significant improvement in statistics and systematics concerning older data.
We will review these experiments and discuss their most recent scientific results.

Speaker: Mirko Boezio (Istituto Nazionale di Fisica Nucleare)

IDM2024_Boezio_final.pdf

10:30 → 11:00 Coffee break

11:00 → 12:30 Plenary

Convener: Carmelo Evoli (Gran Sasso Science Institute)

11:00 Constraining dark matter with 21-cm signals from the Cosmic Dawn

The nature of dark matter (DM) has played a critical role in the formation of the first luminous objects of the universe. A distinguishing characteristic of DM models is their small-scale density fluctuations, which would have affected the abundance of minihalos and the first galaxies, and can be probed through features in the global evolution and spatial fluctuations of the 21-cm signals from neutral hydrogen at cosmic dawn.
In this talk, I’ll first briefly review the effects of DM on the 21-cm signals from cosmic dawn, and the challenges from parameter degeneracies between particle physics and the unknown astrophysics in the early universe. Then I’ll focus on two novel probes, i. e. the velocity acoustic oscillations on the 21-cm power spectrum, and the 21-cm absorption lines against higher-redshift background sources at cosmic dawn, known collectively as the 21-cm forest. In particular, the 21-cm forest are proposed to simultaneously probe the small-scale structures governed by the dark matter particle mass and the early heating history regulated by the formation of first galaxies. By measuring the 1-D power spectrum of the 21-cm forest on high-redshift quasar spectra, the upcoming Square Kilometre Array will be able to shed light on the nature of both the dark matter and the first galaxies.

Speaker: Yidong Xu (NAOC)

XuY_DMwithCD21cm_IDM2024.pptx

11:30 The quest for DM across the gamma-ray spectrum

I will present recent advancements in the search for dark matter (DM) which span a wide energy spectrum from MeV to PeV.
For MeV DM, the INTEGRAL satellite has provided stringent constraints through gamma-ray observations, while X-ray data from the XMM-Newton observatory has offered critical insights into sub-GeV DM, further narrowing the parameter space.
At higher energies, the Fermi Large Area Telescope (Fermi-LAT) has been crucial in probing the GeV to TeV range, particularly focusing on the Galactic center excess, which whose nature is still a mystery. The upcoming Cherenkov Telescope Array (CTA) promises to enhance sensitivity for detecting TeV DM, representing a significant leap forward in our capabilities.
Finally, I will focus on the highest energies, where the Large High Altitude Air Shower Observatory (LHAASO) and the Tibet Air Shower Gamma (Tibet ASγ) experiment extend the search for DM into the PeV regime. These efforts offer unique insights and constraints on ultra-high-energy DM particles, showcasing the potential of multi-wavelength and multi-messenger approaches in the ongoing quest to identify dark matter.

Speaker: Francesca Calore (University of Amsterdam)

IDM2024_07_FCalore.pdf

12:00 Review collisional DM

I will discuss recent advancements in N-body simulations of self-interacting dark matter and their implications for the latest astrophysical observations of diverse galactic systems, including spiral galaxies, ultra-diffuse galaxies, and satellite galaxies of the Milky Way. I will highlight the novel signatures of gravothermal collapse in dark matter halos and explore their detection possibilities through observations of strong lensing systems and supermassive black holes.

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

2024IDMHBYU.pdf

12:30 → 14:00 Lunch

14:00 → 16:00 Parallel 1: Direct detection

Convener: Elisabetta Baracchini (Istituto Nazionale di Fisica Nucleare)

14:00 Directional dark matter searches with the NEWSdm Experiment

The nature of dark matter is one of the most relevant open problems both in cosmology and particle physics. Many different experimental techniques have been designed and built to detect Weakly Interactive Massive Particles (WIMPs) as dark matter candidates via their scattering with detector atoms. The NEWSdm experiment, located in the Gran Sasso underground laboratory in Italy, is based on a novel nuclear emulsion technology with nanometric resolution and new emulsion scanning microscopy that can detect recoil track lengths down to one hundred nanometers. Therefore, it is the most promising technique with nanometric resolution to disentangle the dark matter signal from the neutrino background, with a directional approach meant to overcome the background from neutrinos. The experiment has carried out measurements of neutrons and a run with equatorial telescope is in progress. In this talk we discuss the status of the experiment and we report the first analysis of data taken at Gran Sasso. We also discuss its sensitivity to boosted dark matter, achievable with a 10 kg emulsion module, exposed for one year at the Gran Sasso surface laboratory.

Speaker: Andrey Alexandrov (Istituto Nazionale di Fisica Nucleare)

Alexandrov_IDM2024.pdf

14:20 First Directional Neutron Recoil Results from a 1 m^3 scale SF6 TPC Vessel with a Coupled MMThGEM-Micromegas Readout

Directional Dark Matter (DM) detection, with low pressure gaseous Time Projection Chambers (TPCs), is seen as a viable means for confidently probing below the neutrino fog, for instance in searches planned by CYGNO and the CYGNUS collaboration. Negative Ion Drift (NID) gases like SF6 are essential for reducing drift phase charge diffusion. However, it is notoriously difficult to produce significant charge avalanches in these gases. Recent results from a novel two stage Multi-Mesh Thick Gaseous Electron Multiplier (MMThGEM) have shown that with careful design and optimisation of such a gain charge device, sub 10^5 gas gains can be achieved. This offers an order of magnitude improvement in what was previously considered possible with such a gas. We present results in low pressure SF6 with the MMThGEM, operating as a gain stage device, coupled to a Micromegas readout plane including: gas gain measurements with 55Fe x-rays, a 2D alpha track reconstruction algorithm and neutron recoil measurements in a small test vessel. Finally we present nuclear recoil results in a large 1 m^3 scale detector volume, termed the BENTO vessel, along with supplementary SRIM and SREM simulation results. These results successfully demonstrate the MMThGEM as a gain stage device with a full scale NID target volume.

Speaker: Alasdair McLean (University of Sheffield)

AMcLean-IDM2024.pdf

14:40 Status of NEWAGE: direction-sensitive dark matter search with low background micro-pattern gaseous TPC

The sensitivity of the direct dark matter search is being improved by various energy-sensitive experiments such as XENONnT, LZ, Panda-X and so on. In parallel, direction-sensitive dark matter searches are designed and taken place to reveal properties of the dark matter particle after its discovery or to explore beyond the neutrino fog. NEWAGE is one of the direction-sensitive WIMP search experiments using three-dimensional tracking gaseous TPC, placed in the Kamioka underground observatory. Recently we developed low RI emission micro pattern gas detector. The new detector was installed in the Kamioka underground observatory and the final commissioning was started from the end of 2023. We will present the status of the underground dark matter search and its prospects.

Speaker: Satoshi Higashino (Kobe University)

higashino_IDM2024_20240711.pdf

15:00 The CYGNO experiment, a directional detector for direct Dark Matter searches

CYGNO/INITIUM is an innovative experiment for Dark Matter searches with the purpose of detecting low mass (0.5-50 GeV) WIMPs and performing solar neutrino spectroscopy. This project establishes itself with its strong directionality capabilities, and the use of a gaseous TPC filled with He:CF$_4$, a low density gas mixture sensitive to both spin dependent and independent interactions, at atmospheric pressure and with optical readout.

In CYGNO detectors, the amplification is composed by a stack of three Gas Electron Multipliers (GEMs). Here, the primary electrons are multiplied and, consequently, light is produced due to the scintillating properties of the gas. The characteristic CYGNO light readout is carried out through the combined use of a scientific CMOS camera and PMTs. By merging the information of the two-dimensional projection (X-Y) obtained with a sCMOS camera and the light time profile (dZ) reconstructed using the PMT signal, it is possible to perform a 3D reconstruction of ionizing events. The high granularity and fast sensors of this approach also provide a detailed reconstruction of the characteristic particle's energy deposition, which enables topology, directional and head-to-tail recognition.

This presentation will give an overall review on the status of the CYGNO project and, in particular, the recent underground campaigns carried out between 2022-2024, at the Laboratori Nazionali del Gran Sasso (LNGS), with LIME, a 50 L CYGNO detector. A shielding multistaged approach was implemented, where LIME took data starting from no shielding, then two copper stages with increasing thickness, and finishing with the addition of water surrounding the whole detector. This data was used to measure the different internal and external background components and assess CYGNO data compatibility with Monte Carlo simulation. Complementary, LIME's response over large periods of time and different gas conditions (stability and calibrations) will be briefly discussed as well as the recent progresses concerning particle identification, 3D tracking and combined CMOS-PMT analysis.

CYGNO is currently in the executive design phase of its new detector, CYGNO-04, which consists of a 0.4 m$^3$ TPC that will be built at LNGS, starting from 2025. This detector will determine the capability of the physics reach for future CYGNO detectors, as well as demonstrate the performance and scalability of the CYGNO approach. A brief discussion on the CYGNO-04 design and its physics prospects will also be done.

David J. G. Marques on behalf of the CYGNO collaboration

Speaker: David José Gaspar Marques (Istituto Nazionale di Fisica Nucleare)

IDM24-CYGNO-DavidMarques-presentation

IDM24-CYGNO-DavidMarques.pdf

15:20 DMICA: exploring Dark Matter in natural muscovite MICA

Searching for dark matter typically requires a large amount of material to capture extremely rare interactions. However, natural mineral crystals like mica have been around for geological time scales, offering plenty of exposure even in small samples. These crystals can hold onto nuclear recoil tracks—evidence of dark matter interactions—for periods longer than the Earth's age. When etched, these tracks appear as observable pits. Building on this, Snowden-Ifft and colleagues in 1995 studied natural Muscovite mica that was 500 million years old, covering an area of just 0.08 square millimeters. We're now planning the DMICA experiment to significantly expand upon this initial research, covering much larger areas. In this presentation, we'll discuss our preliminary experiments aimed at replicating Snowden-Ifft's work as a stepping stone for DMICA. We'll also cover how sensitive the DMICA experiment could be in detecting dark matter, emphasizing that mica's large surface area to volume ratio is particularly useful for detecting very heavy dark matter particles.

Speaker: Shigenobu Hirose (JAMSTEC)

20240708_IDM2024.pdf

15:40 Dark Matter Searches with the LEGEND Experiment

The LEGEND (Large Enriched Germanium Experiment for Neutrinoless Double beta decay) is a phased approach for the detection of neutrinoless double beta decay (0vBB) in the Ge-76 candidate isotope for this rare decay. The experimental concept is to deploy high-purity germanium detectors enriched in Ge-76 underground, operated in a bath of liquid argon, which acts as both a shield and a veto mechanism via scintillation. The current phase, LEGEND-200, consists of 140 kg of HPGe detectors (with more to be installed later this year) and is in stable data taking mode at LNGS, with an exposure goal of 1 ton-year. The future LEGEND-1000 phase will consist of 1 ton of HPGe detectors operated in a bath of underground-sourced liquid argon, which will have drastically reduced cosmogenic backgrounds originating from the argon, leading to a quasi background-free spectrum at the ROI for 0vBB (2.039 MeV) after 10 ton-years of exposure.

The scientific results expected from LEGEND encompass more than 0vBB, but a wide range of beyond-standard-model (BSM) physics, including various dark matter (DM) candidates. The precursor experiments, Majorana and GERDA, have had a strong history of BSM searches, and we will continue these efforts in LEGEND. Majorana, for instance, has recent results on searches for exotic dark matter models, from sterile neutrino DM, absorption of fermionic DM, to bosonic DM. With the larger exposure and lower backgrounds expected in the LEGEND experiment as compared to Majorana and GERDA, many of the previous DM searches are expected to be improved upon, as well as having sensitivity to other recently investigated DM models, such as multiple interacting ultraheavy DM. In this talk, I will review the LEGEND experimental concept, predicted backgrounds, and various dark matter candidates that the experiment is well-poised to detect for both the current LEGEND-200 phase and the next-generation LEGEND-1000 phase.

This work is supported by the U.S. DOE and the NSF, the LANL, ORNL and LBNL LDRD programs; the European ERC and Horizon programs; the German DFG, BMBF, and MPG; the Italian INFN; the Polish NCN and MNiSW; the Czech MEYS; the Slovak RDA; the Swiss SNF; the UK STFC; the Russian RFBR; the Canadian NSERC and CFI; the LNGS and SURF facilities.

Speaker: Samuel Watkins (Los Alamos National Laboratory)

watkins_legend_idm2024.pdf

14:00 → 16:00 Parallel 2: Indirect detection

Convener: Giulia Pagliaroli (Istituto Nazionale di Fisica Nucleare)

14:00 Applying Simulation-Based Inference to Spectral and Spatial Information from the Galactic Center Gamma-Ray Excess

The two most favored explanations of the Fermi Galactic Center gamma-ray excess (GCE) are millisecond pulsars and self annihilation of the smooth dark matter halo of the galaxy. In order to distinguish between these possibilities, we would like to optimally use all information in the available data, including photon direction and energy information.
To date, analyses of the GCE have generally treated directional and energy information separately, or have ignored one or the other completely. Here, we develop a method for analyzing the GCE that relies on simulation-based inference with neural posterior models to jointly analyze photon directional and spectral information while correctly accounting for the spatial and energy resolution of the telescope, here assumed to be the Fermi Large Area Telescope (LAT). Our results also have implications for analyses of the diffuse gamma-ray background, which we discuss.

Speaker: Jason Kumar (University of Hawaii)

IDM2024a.pdf

14:20 Robust inference of the Galactic centre gamma-ray excess spatial properties

The gamma-ray Fermi-LAT Galactic centre excess (GCE) has puzzled scientists for over 15 years. Despite ongoing debates about its properties, and especially its spatial distribution, its nature remains elusive. We scrutinize how the estimated spatial morphology of this excess depends on models for the Galactic diffuse emission, focusing particularly on the extent to which the Galactic plane and point sources are masked. Our main aim is to compare a spherically symmetric morphology–potentially arising from the annihilation of dark matter (DM) particles–with a boxy morphology–expected if faint unresolved sources in the Galactic bulge dominate the excess emission. Recent claims favouring a DM-motivated template for the GCE are shown to rely on a specific Galactic bulge template, which performs worse than other templates for the Galactic bulge. We find that a non-parametric model of the Galactic bulge derived from the VVV survey results in a significantly better fit for the GCE than DM-motivated templates. This result is independent of whether a GALPROP-based model or a more non-parametric ring-based model is used to describe the diffuse Galactic emission. This conclusion remains true even when additional freedom is added in the background models, allowing for non-parametric modulation of the model components and substantially improving the fit quality. When adopted, optimized background models provide robust results in terms of preference for a boxy bulge morphology for the GCE, regardless of the mask applied to the Galactic plane.

Speaker: Chris Gordon (University of Canterbury (NZ))

IDM2024.pdf

IDM2024.pptx

14:40 Search for dark matter decay and annihilation using observation by Tibet AS$_\gamma$ and LHAASO

Recently, Tibet AS$_\gamma$ and LHAASO have observed very high energy diffuse gamma rays in the Galactic place between 10 TeV and 1 PeV energies. In our work, we utilize these observations to search for dark matter decay or annihilation signals to Standard Model particles. In addition to the primary gamma-ray originating from various Standard Model particles, we also include secondary gamma-rays generated in these processes. We also consider the effects of dark matter substructures and tidal disruption. We place constraints on dark matter annihilation cross-section and decay lifetime for a wide range of dark matter masses. Future observation of these high-energy gamma rays can further help us either discover particle dark matter or better constrain its properties.

Speaker: Abhishek Dubey (Indian institute of science, Bangalore)

IDM_Abhishek.pdf

15:00 Cosmic-Ray Propagation Models Elucidate the Prospects for Antinuclei Detection

Tentative observations of cosmic-ray antihelium by the AMS-02 collaboration have re-energized the quest to use antinuclei to search for physics beyond the standard model. However, our transition to a data-driven era requires more accurate models of the expected astrophysical antinuclei fluxes. We use a state-of-the-art cosmic-ray propagation model, fit to high-precision antiproton and cosmic-ray nuclei (B, Be, Li) data, to constrain the antinuclei flux from both astrophysical and dark matter annihilation models. We show that astro-physical sources are capable of producing O(1) antideuteron events and O(0.1) antihelium-3 events over 15 years of AMS-02 observations. Standard dark matter models could potentially produce higher levels of these antinuclei, but showing a different energy-dependence. Given the uncertainties in these models, dark matter annihilation is still the most promising candidate to explain preliminary AMS-02 results. Meanwhile, any robust detection of antihelium-4 events would require more novel dark matter model building or a new astrophisical production mechanism.

Speaker: Pedro De la Torre Luque (Institute of theoretical physics (IFT))

IDM_Antinuclei_DelaTorreLuque.pdf

15:20 Emulation of cosmic-ray antideuteron fluxes from dark matter annihilation

Cosmic-ray antimatter, particularly low-energy antideuterons, constitute a sensitive probe of dark matter annihilating in our Galaxy. We study this smoking-gun signature and explore its complementary to indirect search via cosmic-ray antiprotons. We revisit the Monte Carlo simulation of antideuteron coalescence and cosmic-ray propagation, allowing us to assess uncertainties from both processes. In particular, we incorporate uncertainties in the $\Lambda_b$ production rate and the coalescence momentum and consider two distinctly different propagation models. To this end, we further the development of the neutral emulator DarkRayNet enabling a fast prediction of propagated antideuteron energy spectra for a wide range of annihilation channels and any admixtures thereof. We find that our network can predict the various spectra with excellent accuracy, offering a significant speed-up over the full simulation. Employing the network's output, we then test the detectability of antideuterons from dark matter annihilation with AMS-02 and the upcoming GAPS experiment for a wide range of dark matter masses.

Speaker: Lena Rathmann (RWTH Aachen University)

IDM2024_Rathmann.key

IDM2024_Rathmann.pdf

15:40 The GAPS experiment: low energy cosmic-ray antinuclei for indirect dark matter searches

The General Antiparticle Spectrometer (GAPS) is a balloon-borne experiment designed to perform
low-energy cosmic-ray antinuclei measurements searching for indirect signatures of dark matter.
A wide range of well-motivated dark matter models predicts antideuteron and antihelium fluxes
about two orders of magnitude above the expected astrophysical background below 250 MeV/n.
Thanks to a novel identification technique based on the formation of an exotic
atom and its de-excitation and decay, GAPS will achieve an unprecedented
sensitivity for low-energy antideuteron and antihelium nuclei fluxes.
The GAPS experiment will perform three long-duration balloon flights over
Antarctica, the first of which is planned for the 2024/2025 Austral summer. The experimental
apparatus consists of a Si(Li) tracker surrounded by a time-of-flight system made of plastic
scintillator paddles. This contribution will illustrate the scientific potential of
the GAPS experiment and its impact on indirect dark matter searches.
Then, the final phases of the integration, calibration, and the results of the system's ground tests
will be discussed in view of the launch from the Mc Murdo Antarctic base in December 2024.

Speaker: Riccardo Munini (Istituto Nazionale di Fisica Nucleare)

GAPS_IDM_RiccardoMunini.pdf

14:00 → 16:00 Parallel 3: Light Dark Matter

Convener: Paolo Agnes (GSSI)

14:00 The Light Dark Matter eXperiment (LDMX)

The constituents of dark matter are still unknown, and the viable possibilities span a very large mass range. Specific scenarios for the origin of dark matter sharpen the focus on a narrower range of masses: the natural scenario where dark matter originates from thermal contact with familiar matter in the early Universe requires the DM mass to lie within about an MeV to 100 TeV. Considerable experimental attention has been given to exploring Weakly Interacting Massive Particles in the upper end of this range (few GeV – ~TeV), while the region ~MeV to ~GeV is largely unexplored. Most of the stable constituents of known matter have masses in this lower range, tantalizing hints for physics beyond the Standard Model have been found here, and a thermal origin for dark matter works in a simple and predictive manner in this mass range as well. It is therefore an exploration priority. If there is an interaction between light DM and ordinary matter, as there must be in the case of a thermal origin, then there necessarily is a production mechanism in accelerator-based experiments. The most sensitive way (if the interaction is not electron-phobic) to search for this production is to use a primary-electron beam to produce DM in fixed-target collisions. The Light Dark Matter eXperiment (LDMX) is a planned electron-beam fixed-target missing-momentum experiment that has unique sensitivity to light DM in the sub-GeV range. This contribution will give an overview of the theoretical motivation, the main experimental challenges and how they are addressed, as well as projected sensitivities in comparison to other experiments.

Speaker: Einar Elén (Lund university)

IDM.pdf

14:20 Searches for dark sector particles at Belle and Belle II

The Belle and Belle$~$II experiment have collected samples of $e^+e^-$ collision data at centre-of-mass energies near the $\Upsilon(nS)$ resonances. These data have constrained kinematics and low multiplicity, which allow searches for dark sector particles in the mass range from a few MeV to 10$~$GeV. Using a 426$~$fb$^{-1}$ sample collected by Belle$~$II, we search for a light dark photon that could explain the ATOMKI anomaly and a $Z^{\prime}$ boson that decays invisibly. Using a 711$~$fb$^{-1}$ sample collected by Belle, we search for $B\to h + \mathrm{invisible}$ decays, where $h$ is a $\pi$, $K$, $D$, $D_{s}$ or $p$, and $B\to Ka$, where $a$ is an axion-like particle.

Speaker: Doris Y Kim

IDM DorisKim v4.pdf

14:40 The X17 search with the PADME experiment

The Positron Annihilation into Dark Matter Experiment (PADME) has been designed with the intention to look for a signal of a dark photon [1], but it can investigate the existence of different feebly interacting particles (FIPs) produced in the interaction of a positron beam with a thin diamond target [2]. These particles are predicted by theories beyond the Standard Model developed to address the dark-matter problem with alternative approaches to the WIMP theory. In recent years, a nuclear physics experiment conducted at the ATOMKI of Debrecen reported an anomaly studying the de-excitation of $^8$Be via Internal Pair Creation that might represents the first evidence of a FIP of mass $\sim$17 MeV (X17) [3]. PADME has the unique possibility to verify the existence of this particle, by trying to produce resonantly the X17 via electron-positron annihilation studies [4]. This paper presents the experimental technique developed by the collaboration and the preliminary results of the ongoing analysis.
References
[1] B. Holdom, Phys. Lett. B 178 (1986) 65–70.
[2] P. Albicocco et al., JINST 17 (2022) 08, P08032.
[3] A. J. Krasznahorkay, et al., Phys. Rev. Lett. 116 (4) (2016) 042501.
[4] E. Nardi, C. D. R. Carvajal, A. Ghoshal, D. Meloni, M. Raggi, Phys. Rev. D 97 (9) (2018) 095004.

Speaker: Marco Mancini

IDM24_MM.pdf

15:00 SPICE: a Solid State Dark Matter Direct Detection Experiment from the TESSERACT Collaboration

The TESSERACT collaboration searches for ``Light" (MeV-GeV) Dark Matter with a variety of target materials: solid state targets in the case of the SPICE experiment, and superfluid helium as a part of the HeRALD experiment. In my talk, I will give an overview of the SPICE experiment, which uses sapphire and other crystalline targets to probe multiple light dark matter models. I will show results from 373 meV \sigma energy resolution gram scale prototype SPICE detectors, and discuss recent advancements in developing low background TES-based detectors for use by our entire collaboration. The energy resolution of and low energy backgrounds in these detectors are set by a new class of stress-induced backgrounds, which I will conclude by discussing.

Speaker: Roger Romani (UC Berkeley)

Romani_IDM_2024.pdf

15:20 Recent progress towards the HeRALD detector for light dark matter with superfluid helium

The TESSERACT suite of experiments will deliver sensitivity to multiple models of sub-GeV dark matter via complementary targets, including GaAs and sapphire (referred to as SPICE) and superfluid helium (referred to as HeRALD). HeRALD uses the same TES sensor technology as SPICE to read multiple signal channels from superfluid helium: prompt scintillation, rotons, and triplet excimers. I will discuss recent R&D towards the realization of the HeRALD concept, its advantages in the discrimination against stress-induced instrumental backgrounds and physical backgrounds with multiple signal channels, its projected sensitivity, and plans for underground deployment.

Speaker: Scott Haselschwardt (Lawrence Berkeley National Lab)

HeRALD_IDM_2024_v2.pdf

15:40 Prospects for DarkSide-20k sensitivity to light dark matter particles

DarkSide-20k, currently under construction at LNGS, is a liquid argon double-phase Time Projection Chamber designed for the direct detection of Weakly Interacting Massive Particles (WIMPs) with masses exceeding 10 GeV/c². In addition to its primary goal, DarkSide-20k has a significant potential for discovering light dark matter particles. Building on the success of its predecessor, DarkSide-50, which set world-best limits on WIMPs in the 1.2 to 3.6 GeV/c² mass range with ~1,000 times smaller target mass, DarkSide-20k presents unprecedented sensitivity prospects for low mass (1-10 GeV/c²) WIMPs and other light dark matter candidates.

Speaker: Marie van Uffelen (CPPM, Aix Marseille Université, CNRS/IN2P3)

202407_IDM_DS20klowmass_MvanUffelen.pdf

16:00 → 16:30 Coffee break

16:30 → 18:50 Parallel 1: Direct detection

Convener: Paolo Agnes (GSSI)

16:30 Studying hydrogen-xenon mixtures for direct dark matter detection

Adding a light element such as hydrogen to xenon dark matter detectors is projected to expand experimental sensitivity to sub-GeV dark matter. The HydroX effort is exploring this technology for future dark matter experiments. As part of this effort, we have built a test stand at SLAC to study the signal properties of hydrogen-doped xenon dark matter detectors. I will discuss the design of the test stand, which consists of an instrumented gaseous xenon time projection chamber and piping system, as well as a separate vessel for hydrogen after-pulsing studies. Preliminary commissioning data will be presented, and future run plans will be discussed.

Speaker: Ann Wang (Stanford/SLAC)

IDM2024_AWang_talk.pdf

16:50 Characterization of low energy argon recoils with ReD and ReD+

The Recoil Directionality project (ReD) within the Global Argon Dark
Matter Collaboration characterized the response of a liquid argon (LAr) dual-phase Time Projection Chamber (TPC) to neutron-induced nuclear recoils, to measure the charge yield at low-energy. The charge yield is a critical parameter for the experiments searching for dark matter in the form of low-mass WIMPs and measurements in Ar below 10 keV are scarce in the literature. ReD was designed to cover the gap down to 2 keV.

The ReD data taking took place in 2023 at the INFN Sezione di Catania. The TPC was irradiated by neutrons produced by an intense $^{252}$Cf fission source in order to produce Ar recoils in the energy range of interest. The energy of the nuclear recoils produced within the TPC by (n,n') scattering was determined by detecting the outgoing neutrons by a dedicated neutron spectrometer made of 18 plastic scintillators. The kinetic energy of neutrons interacting in the TPC was evaluated event by-event by measuring the time of flight. Data analysis is currently being finalized, but it has been confirmed that ReD collected and characterized a sample of nuclear recoils down to 2 keV, thus meeting its design goal.

The ReD effort will be further extended by a new project, ReD+, funded by a PRIN grant from the Italian Ministry of Research. ReD+ is designed to push the sensitivity down to 0.5 keV, by using the same conceptual design of ReD and improved components. A new TPC is being re designed and optimized in order to increase the signal rate and the signal-to background ratio, which limited the sensitivity of ReD.

In this contribution, we describe the experimental setup and the preliminary results from the data analysis of ReD, as well as the perspectives to further lower the coverage down to the sub-keV range with ReD+.

Speaker: Luciano Pandola (Istituto Nazionale di Fisica Nucleare)

Pandola-IDM2024-ReD.pdf

17:10 XLZD: A Next-Generation Liquid Xenon Observatory for Dark Matter & Neutrino Physics

Liquid xenon time projection chambers are nowadays recognized as the leading technology for dark matter direct detection. The XENON and LUX/LZ projects have been exploring the parameter space for WIMPs and other rare events for decades.
In this talk, we will present the forthcoming phase of the project: XLZD, which from the merging of the two currently leading experiments XENONnT and LZ, aims to designing and building the ultimate liquid xenon dark matter detector.
XLZD will feature a 60-ton active mass, with reduced Rn and neutron backgrounds, leaving neutrinos as the main background. It will explore the entire WIMP parameter space down to the neutrino fog limit and, at the same time, it will also present good sensitivity to neutrino-less double-beta decay of 136Xe, and the possibility to study solar neutrinos with unprecedented sensitivity.

Speaker: Laura Baudis (Univeristy of Zurich)

baudis_idm24.pdf

17:30 The DARWIN R&Ds towards the XLZD detector

Experiments using dual-phase liquid xenon time projection chambers (TPCs) are among the most sensitive in looking for weak interactive massive particle (WIMP) dark matter in the GeV to TeV energy range. Current generation of detectors use ~10 tonnes of liquid xenon to reach sensitivities of 10$^{-47}$ cm$^2$. The ultimate goal of these experiments is to explore the allowed parameter space for nuclear recoils down to the neutrino fog, after which directionality is needed to discriminate WIMPs from coherent neutrino-nucleus scattering. To reach this goal we need ~60 tonnes of liquid xenon and thus a TPC of ~3 m height and width. The DARWIN program has the purpose to develop the required technology to overcome the challenges in building and operating a detector of these dimensions. In this talk I will show an overview of the challenges and the ongoing R&Ds carried out under the DARWIN flagship in view of a 60 tonnes dual-phase TPC envisioned by the XLZD (XENON-LZ-DARWIN) collaboration.

Speaker: Chiara Capelli (University of Zurich)

IDM24_Capelli.pdf

17:50 Material assay campaign of the DarkSide-20k experiment

The DarkSide-20k experiment will search for dark matter in the form of WIMPs and has the potential to establish the most stringent limits for the spin-independent interaction of heavy WIMPs with nucleons. The background requirement of this experiment is less than 0.1 events in 200 tonne years, which ranks among the most rigorous ever set in the field of rare event searches and establishes stringent criteria in terms of radiopurity of the detector materials. During recent years, a comprehensive assay campaign has been conducted to assess the radiopurity of candidate components of the detector, with particular attention to the U and Th decay chains. Various assay techniques have been employed to detect the chain parents (ICPMS), the gamma emitters along the chain (HPGe), and the Po-210 content in the bulk of the materials. This approach allows for a systematic investigation of the secular equilibrium of the decay chain in all the materials. Special emphasis is placed on estimating neutron yields. A specific mass spectrometry campaign has been integrated into the contamination measurement to determine the chemical composition of the critical components of the detector, thereby reducing the uncertainty of the neutron yield produced through (a,n) reactions. Concurrently, SaG4n, a Geant4-based open code developed within the framework of DarkSide, has been developed and utilized to calculate the neutron yield induced by (a,n) reactions, with alphas primarily originating from the radioactive chains.

In this presentation, we outline the organization of the assay campaign along with its results to date, as well as the new (a,n) calculation techniques developed within the context of the DS-20k experiment.

Speaker: Roberto Santorelli (CIEMAT)

IDM2024_Santorelli.pdf

16:30 → 18:50 Parallel 2: Indirect detection

Convener: Carmelo Evoli (Gran Sasso Science Institute)

16:30 The Pierre Auger Observatory and Super-Heavy Dark Matter

We discuss the connection of the Pierre Auger Observatory data with a large class of dark matter models based on the early-universe generation of super-heavy particles, their role in the solution of the dark matter problem, highlighting the remarkable constraining capabilities of the Auger observations.

Speaker: Roberto Aloisio (GSSI & INFN)

Aloisio-IDM24.pdf

16:50 Dark Matter Gamma-ray searches in Galaxy Clusters: status and prospects

Galaxy clusters are the largest gravitationally bound structures in the Universe, being completely dark matter (DM) dominated objects. The expected gamma-ray flux from annihilation/decay of DM depends on the target's DM density and its distance to Earth. Thus, for DM decay, local galaxy clusters yield the highest expected fluxes compared to other possible targets, as they are the most massive structures in the Universe. Regarding DM annihilation, clusters can provide fluxes comparable to the ones from dwarf spheroidal galaxies as long as the DM interactions expected in their substructures are taken into account. In this talk, I will present the analysis of 12 years of Fermi-LAT data in the direction of 49 clusters. From the combined search, we found a signal of 2.5-3.0 sigma significance, potentially associated either with DM or hadronic induced emission produced in the intracluster region by cosmic rays colliding with gas and photon fields. Finally, looking into the future, I will also discuss the prospects of the coming Cherenkov Telescope Array Observatory (CTAO), to detect diffuse gamma-ray emission from the Perseus galaxy cluster, where we derive the tightest constraints for DM decay scenarios in the TeV range.

Speaker: Judit Pérez-Romero (CAC/UNG)

IDM24_ID_JPR.pdf

17:10 Unveiling dark sub-haloes in the Galactic plane with the Cherenkov Telescope Array Observatory

Numerous observations point towards the existence of dark matter (DM) at astrophysical and cosmological scales, yet the fundamental nature of this elusive component of our universe remains unknown. Theory and simulations of galaxy formation predict that DM should cluster on small scales in bound structures called sub-halos or DM clumps. Sub-halos are abundant in the Galaxy and can produce high-energy gamma rays as final products of DM annihilation. Recently, it has been highlighted that the brightest halos should also have a sizeable extension in the sky. In this study, we examine the prospects offered by CTAO for detecting and characterizing such objects. From simple models for individual sub-halos and their population in the Milky Way including tidal effects, we examine under which conditions such sources can be identified in data collected by the Galactic plane survey proposed by the CTAO consortium. We use a full spatial-spectral likelihood analysis to derive the sensitivity of CTAO to extended DM sub-halo emission. We find that the brightest sub-halos of the Galactic population are detected at the 5$\sigma$ level for annihilation ($b\bar{b}$) cross-sections $\langle \sigma v\rangle \sim 1\times10^{-24}$ cm$^3$/s of TeV-scale DM. This minimal cross-section for detection is almost sufficient to discriminate such a sub-halo from a point-like astrophysical source. We also assess the CTAO sensitivity prospects for the full sub-halo population depending on their resilience to tidal effects in the Galactic potential.

Speaker: Christopher Eckner (University of Nova Gorica, Center for Astrophysics and Cosmology)

IDM_2024_DMsubhalos_in_GPS_Eckner.pdf

17:30 The viability of low-mass subhaloes as targets for gamma-ray dark matter searches

In this talk, we investigate the discovery potential of low-mass Galactic dark matter (DM) subhaloes for indirect searches of DM. We use data from the Via Lactea II (VL-II) N-body cosmological simulation, which resolves subhaloes down to $\mathcal{O}(10^4)$ solar masses and it is thus ideal for this purpose.
First, we characterize the abundance, distribution and structural properties of the VL-II subhalo population in terms of both subhalo masses and maximum circular velocities. Then, we repopulate the original simulation with millions of subhaloes of masses way below the minimum VL-II subhalo resolution. We compute subhalo DM annihilation astrophysical "J-factors" and angular sizes for the entire subhalo population, by placing the Earth at a random position but at the right galactocentric distance in the simulation. Thousands of these realizations are generated in order to obtain statistically meaningful results.
We find that some nearby low-mass Galactic subhaloes, not massive enough to retain stars or gas, may indeed yield DM annihilation fluxes comparable to those expected from other, more massive and acknowledgeable DM targets like dwarf satellite galaxies. Typical angular sizes are of the order of the degree, thus subhaloes potentially appearing as extended sources in gamma-ray telescopes, depending on instrument angular resolution and sensitivity. Our work shows that low-mass Galactic subhaloes with no visible counterparts are expected to play a relevant role in current and future indirect DM searches and should indeed be considered as excellent DM targets.

Speaker: Alejandra Aguirre-Santaella (Institute for Computational Cosmology, Durham University)

AAS-IDM2024-July11.ppsx

17:50 The timescales for dark matter heating of old neutron stars

Neutron stars (NSs) are promising cosmic laboratories to test the nature of dark matter (DM). DM captured by the strong gravitational field of these stellar remnants transfers its kinetic energy to the star through subsequent collisions with the star constituents. Further DM annihilation can add extra heating. This can produce anomalous heating of old neutron stars. While DM deposits its kinetic energy quite quickly, in order for appreciable annihilation heating to be achieved, capture and annihilation processes should reach a state of equilibrium. In light of this, we revisit the calculation of the DM capture rate, thermalization, and capture-annihilation equilibrium timescales in NSs, making little approximations about the physics of neutron stars. We show that capture-annihilation equilibrium, and hence maximal annihilation heating, can be achieved without complete thermalization of the captured dark matter for all types of dark matter - baryon interactions. This includes cases where the scattering or annihilation cross sections are momentum or velocity suppressed in the non-relativistic limit. For scattering cross sections that saturate the capture rate, we find that capture-annihilation equilibrium is typically reached on a timescale of less than $1$ year for vector interactions and $10^4$ years for scalar interactions.

Speaker: Sandra Robles (Fermilab)

Timescales_DM_heating_NSs.pdf

18:10 New 511 keV line data provides strongest sub-GeV dark matter constraints

We explore the $511$ keV emission associated to sub-GeV dark matter (DM) particles that can produce electron-positron pairs and form positronium after thermalizing. We use $\sim16$ yr of SPI data from INTEGRAL to constrain DM properties, including the full positron propagation and losses, and the free electron density suppression away from the Galactic plane. We show that the predicted longitude and latitude profiles vary significantly for different DM masses, unlike previous assumptions, and obtain the strongest limits on sub-GeV DM (from the MeV to a few GeV) so far, excluding cross-sections down to $\langle \sigma v \rangle \lesssim10^{-32}$ cm$^3$ s$^{-1}$ for $m_{\chi}\sim1\,\text{MeV}$ and $\langle \sigma v \rangle \lesssim10^{-26}$ cm$^3$ s$^{-1} $ for $m_{\chi}\sim5\,\text{GeV}$ and lifetimes up to $\tau \gtrsim 10^{29}\, \textrm{s}$ for $ m_{\chi}\sim1\,\text{MeV} $ and $\tau \gtrsim 10^{27}\,\textrm{s}$ for $m_{\chi}\sim5$ GeV for the typical Navarro-Frenk-White DM profile. Our derived limits are robust within a factor of a few due to systematic uncertainties.

Speaker: Shyam Balaji (King's College London)

ID2024_Seminar-1.pdf

18:30 Hunting for dark matter and dark photon-photon trident

We discuss a novel decay process for dark matter searches known as the dark photon-photon trident, where a dark photon can interact with Standard Model particles through kinetic mixing with the visible photon, producing three-photon final states. Indirect searches for this process are categorized into two scenarios. Firstly, dark photons can be produced by dark matter annihilation in celestial objects and dwarf galaxies. Secondly, the dark photon can itself constitute dark matter, which decays into photons falling into the energy range of X-ray observations. We give constraints on dark matter-Standard Model interactions and the dark photon parameter space based on these search strategies.

Speaker: Thong Nguyen (Stockholm University)

IDM2024_ThongNguyen.pdf

16:30 → 18:50 Parallel 3: Light Dark Matter

Convener: Elisabetta Baracchini (Istituto Nazionale di Fisica Nucleare)

16:30 Searching for Millicharged Particles from the eV to GeV mass scale with Skipper-CCDs

Millicharged particles (mCPs) appear in many extensions of the standard model. They are characterized by having a fractional electric charge and can be a compelling DM candidate to solve anomalies in both particle physics and cosmology. They could be created on Earth through meson decays in accelerator facilities or through compton-like processes in nuclear reactors. Due to their small electric charge, their detection remains elusive. Taking advantage of the low ionization threshold, and the sub-electron noise of Skipper-CCDs, the SENSEI collaboration recently published direct detection constraints with a small gram-scale detector at the neutrino beamline at Fermilab establishing this technology as an ideal candidate to advance mCP searches with dedicated, more massive experiments. In this talk, I will present the SENSEI result, report on the mCP search by the CONNIE and ATUCHA collaborations in nuclear reactors, and present a future experiment (DarkBeaTs) that can greatly extend the sensitivity of mCPs at accelerators by tracking single electron depositions through a stack of Skipper-CCDs to reject background sources. I will also discuss other opportunities for mCP searches at accelerator facilities like the new Skipper-CCD detector installed at the CMS service cavern near the interaction point of the LHC at CERN, or the future PIP-II at Fermilab.

Speaker: Santiago Perez (Fermilab)

IDM 2024 - MILLICHARGED_SkipperCCD.pdf

16:50 Oscura: a 10 kg skipper-CCD detector to search for dark matter

The electron-counting capability and low-energy threshold (~eV) of the skipper-CCDs make them sensitive to low energy interactions. Skipper-CCD experiments with active mass below 100 g searching for dark matter (DM) have achieved very low background rates, allowing them to impose world-leading limits on sub-GeV DM-electron interactions. Motivated by these results, the development of kg-size skipper-CCD DM experiments aiming for lower backgrounds is on its way. The Oscura experiment is the largest of these efforts and will have unprecedented sensitivity to well-motivated DM benchmark models. During its R&D and design phases, huge progress has been made towards building the ~20,000 skipper-CCD array. In this talk, I will present the overall design of the Oscura detector and its scientific reach. I will discuss the latest progress on the sensors, electronics and background control for Oscura and future plans.

Speaker: Brenda Aurea Cervantes Vergara (Fermilab)

IDM2024_BrendaCervantes.pdf

17:10 The DarkNESS mission: searching for dark matter with a Skipper-CCD satellite observatory

The invention of Skipper-CCDs with sub-electron noise paved the way for groundbreaking low-threshold dark matter (DM) experiments, such as DAMIC and SENSEI. Conventionally, these experiments are deployed underground to mitigate cosmogenic backgrounds; however, some DM signatures are inaccessible to underground experiments due to attenuation in the Earth’s atmosphere and crust. The DarkNESS mission will deploy an array of Skipper-CCDs on a 6U CubeSat in Low Earth Orbit (LEO) to search for electron recoils from strongly-interacting sub-GeV DM as well as X-ray line signatures from sterile neutrino decay. Using a series of observations from LEO, the DarkNESS mission will set competitive upper limits on the DM-electron scattering cross section and help resolve the experimental conundrum associated with the purported observation of a 3.5 keV X-ray line, potentially produced from decaying dark matter. This work will describe the DarkNESS instrument, the technical challenges in operating Skipper-CCDs in the space environment, the scientific objectives of the DarkNESS mission, and the DM parameter space that DarkNESS will probe.

Speaker: Nate Saffold (Fermilab)

DarkNESS-IDM2024-Saffold.pdf

17:30 Dark matter searches using low-energy data of Super-Kamiokande

Neutrino experiments have long been pivotal in the search for WIMP-induced signals through indirect detection. By analyzing excess neutrinos from various sources, such as the Galactic center, Sun, or Earth, beyond the atmospheric neutrino background, competitive sensitivity to WIMPs with masses as low as 1 GeV has been achieved.
Null results from WIMP searches have led innovative approaches in leveraging current and upcoming neutrino experiments for dark matter searches. For instance, there is growing interest in scenarios predicting boosted dark matter, which can be directly observed in experimental volumes.
The Super-Kamiokande (SK) detector, the world's largest water Cherenkov detector tank, is sensitive to both O(1) - O(100) GeV neutrinos produced by WIMP annihilation and O(1) - O(100) MeV signals expected from boosted dark matter scattering.
This talk will summarize recent findings and ongoing analyses in indirect and direct dark matter searches using the Super-Kamiokande detector. Techniques employed in the pursuit of light dark matter, such as neutron tagging with gadolinium-doped water and the application of Machine Learning, will be discussed.

Speaker: Koun Choi (IBS)

IDM2024_Koun_Choi.pdf

17:50 Discovery potential of fermionic dark matter by using the Xe Charged Current tagging in KamLAND-Zen.

The existence of dark matter is strongly supported by astronomical and cosmological observations. There are various experiments searching for dark matter with masses of 10-1000 GeV. However, it has not yet been detected.
Recently, low-mass dark matter has attracted attention as an alternative candidate. In particular, fermionic dark matter (FDM) has been proposed. FDM is absorbed by xenon nuclei and recoil electrons are emitted in the interaction. Then the FDM-absorbing Xe is excited to 136Cs. We can observe recoil electrons and de-excited gamma rays from 136Cs.
Recently, low-lying isomeric states with lifetimes on the order of 100 ns have been observed in 136Cs. This study suggests that delayed coincidence measurements are possible by detecting multiple time-correlated γ-rays emitted from 136Cs*.
The KamLAND-Zen experiment, situated in α deep underground laboratory, houses the largest amount of 136Xe.
We will report on the discovery potential of FDM with KamLAND-Zen.

Speaker: Koga Tachibana (RCNS, Tohoku University)

IDM2024_tachibana.pdf

18:10 Exploring the Low-Energy 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: Alberto Ressa (Istituto Nazionale di Fisica Nucleare)

IDM24_CUORE_Ressa.pdf

18:30 Boosted sub-GeV Dark Matter from Primordial Black Holes in DarkSide-50

The direct detection of sub-GeV dark matter interacting with nucleons is hampered by the low recoil energies induced by scatterings in the detectors. This experimental difficulty is avoided in the scenario of boosted dark matter where a component of dark matter particles is endowed with large kinetic energies. By focusing on the concept of boosted dark matter, wherein a subset of dark matter particles possesses significant kinetic energies, we identify the current evaporation of primordial black holes, ranging in mass from $10^{14}$ to $10^{16}$ grams, as a potential source of such particles with energies ranging from tens to hundreds of MeV. Specifically, we investigate the implications of this phenomenon on the DarkSide-50 experiment, demonstrating that relativistic dark matter particles originating from primordial black holes could yield signals orders of magnitude larger than existing upper bounds. Consequently, we propose that this avenue enables the constraint of the combined parameter space encompassing primordial black holes and sub-GeV dark matter. Additionally, we provide preliminary forecasts on the potential impact of these findings on the upcoming DarkSide-20k experiment.

Speaker: Roberta Calabrese (INFN - Sezione di Napoli)

RC_IDM.pdf

19:30 → 23:00 Social dinner

Dinner.pdf

Friday, 12 July

09:00 → 10:30 Plenary

09:30 SUSY status in light of LHC and WIMP search experiments

There is rampant pessimism in the collder and dark matter communities
regarding the prospects for SUSY dark matter, but this is based on old
prejudices from the 20th century. A proper calculation of electroweak
finetuning reveals the LSP should be a light higgsino state which is
thermally underproduced. But solving the strong CP problem requires
a QCD axion, and the DFSZ model which requires two Higgs doublets
melds well with SUSY. In fact, SUSY and axions solve several problems
on each side: for instance, intrinsically SUSY discrete R-symmetries
which arise from string compactifications yield R-parity conservation and
allow PQ to emerge as an accidental, approximate global U(1) while
solving the SUSY mu problem where the PQ scale f_a then related to the
hidden sector SUSY breaking scale ~10^11 GeV, in the cosmological sweet spot.
Dark matter is then a mixture of DFSZ axions and higgsino-like WIMPs,
the latter with a diminished abundance: mainly axions.
The axion-photon coupling is quite diminished
due to the presence of higgsinos. The relic abundance requires eight-coupled
Boltzmann equations which account also for saxions and axinos in the
early universe. The effect of light stringy moduli (LSM)
fields is also addressed, and seems to require m(LSM)>~5 PeV to avoid
overproduction of higgsino-like WIMPs.

Speaker: Howard Baer (University of Oklahoma)

IDM2024.pdf

10:00 Search for DM annual modulation with NaI-based detectors

DAMA/LIBRA has successfully developed ultra-high purity NaI(Tl) detectors which have been operated underground for about 20 years. A modulation signal compatible with the expected DM modulation is observed with an exposure of order 3 ton x yr. Any hint of a possible observation of a DM signal deserves deep examination. Therefore, testing the DAMA/LIBRA finding is of crucial interest and in particular probing the amplitude and phase of the modulation. In the last 10 years the effort to probe the DAMA/LIBRA finding on annual modulation has increased intensively. ANAIS-112 and COSINE-100 by using the same target as DAMA/LIBRA have provided important inputs on this search proving that a conclusive result is accessible and currently limited by statistics, with an exposure of order 0.2-0.3 ton x yr. In addition, more efforts are underway to improve the radiopurity of crystals at the level of DAMA/LIBRA or better. This is a crucial step to definitively probe the DAMA/LIBRA results. Besides crystal radiopurity new techniques are being considered to exploit NaI-based detectors for this physics case. In this talk a review of the present results and efforts is reported and near future prospects are discussed.

Speaker: Aldo Ianni (Istituto Nazionale di Fisica Nucleare)

IDM2024-Ianni.pdf

10:30 → 11:00 Coffee break

11:00 → 12:30 Plenary

Convener: Neil Spooner (University of Sheffield)

11:00 Wrap-up (Theory)

Speaker: Katherine Freese (University of Texas, Austin)

DM IDM_KF.pdf

11:30 Wrap-up (Exp)

Speaker: Jocelyn Monroe (University of Oxford)

monroe_IDM_2024.pdf

12:00 Award ceremony and closure

awards.pdf

IDM2024_Closure.pdf

12:30 → 14:00 Lunch

14:00 → 19:00 Excursions

Excurions-Shuttles.pdf

14:00 → 19:00 Gran Sasso National Laboratories visit