Identification of Dark Matter 2026

1 Jun 2026, 08:30 → 5 Jun 2026, 22:00 Europe/Madrid

Paraninfo, University of Zaragoza

Igor García Irastorza (Universidad de Zaragoza), María Luisa Sarsa (CAPA, Universidad de Zaragoza)

The goal of this conference is to present a comprehensive overview of the status of dark matter searches, covering theoretical and experimental perspectives across theories, candidates, and detection strategies while also providing insights into the technological advances in detection techniques that will impact the prospects for finding clues about the nature of the dark matter.

IDM 2026 is scheduled as an in-person conference on June 1-5, 2026 and it will be held in Zaragoza, Spain, organized by the Centro de Astropartículas y Física de Altas Energías (CAPA).

 

Abstract submission is now closed

Registration is now closed. 

Accommodation options can be found in link. 

 

Zaragoza is the fourth largest city in Spain. Located on the banks of the Ebro River, halfway between Madrid and Barcelona, it is the capital of the Region of Aragon. Come and discover this open and friendly city with a long-standing history.

Zaragoza is about 320 km from Madrid and 290 km from Barcelona, well connected with the rest of Spain and the world. It can be easily reached by public transport.

The University of Zaragoza has a recognized track record of expertise in direct dark matter searches and axion physics with a close link to the Canfranc Underground Laboratory, one of the most relevant underground facilities worldwide.

 

Aura_HowToReach.pdf

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poster_idm2026.pdf

Monday 1 June

REGISTRATION

Plenary Session

Convener: Sven Heinemeyer (IFT (CSIC, Madrid))

1 OPENING

Speakers: Igor García Irastorza (Centro de Astropartículas y Física de Altas Energías (CAPA) - Universidad de Zaragoza), María Luisa Sarsa (CAPA, Universidad de Zaragoza)

opening_IDM2026.pdf

2 A health check on the LCDM model

The ``Lambda cold dark matter'' (LCDM) cosmological model is one of
the great achievements in Physics of the past thirty
years. Theoretical predictions formulated in the 1980s turned out to
agree remarkably well with measurements, performed decades later, of
the galaxy distribution and the temperature structure of the cosmic
microwave background radiation. Now a number of
observations have suggested possible discrepancies with LCDM both on
large and small scales. I will discuss some of these discrepancies
including with recent data from DESI, the largest galaxy
survey ever undertaken, as well as constraints on the mass of the one
component of dark matter whose identity we know: neutrinos.

Speaker: Carlos Frenk (Durham University)

zaragoza_idm_26_clean.pptx

3 Constraining the dark sectors of the Universe with the Euclid mission

Following its successful launch in July 2023 and the start of its scientific survey in February 2024, Euclid has become the first stage-IV photometric survey in operations. In addition to its photometric observations, Euclid is also conducting a spectroscopic survey, which allows us to add even more probes to a combined analysis from Euclid data alone. In this talk I will present the forecasts for a combined analysis at the end of the mission, focusing in particular on how combining multiple probes helps break parameter degeneracies and leads to tighter constraints on dark matter and dark energy. I will conclude by outlining current efforts toward a combined analysis with Euclid's first data release.

Speaker: Isaac Tutusaus (ICE-CSIC/IEEC/IRAP)

IDM2026_itutusaus.pdf

4 Dark Matter candidates circa 2026: the WIMPs and beyond the WIMPs

Almost a century after its discovery, Dark Matter has not been identified yet. Even worse, the candidates that were more promising a few years/decades ago, those that the community was betting to find “just around the corner", have not shown up in the ever-improving searches. Hence theorists have gone back to the drawing board and restarted exploring a wider range of possibilities. Many new ideas have been proposed, and some old ideas have been rediscovered. In this talk I will present a (necessarily biased and personal) view of some Dark Matter candidates. I will argue that the cherished WIMPs (Weakly Interacting Massive Particles) should not be dismissed yet, but also that other candidates are well motivated, interesting and worth looking for.

Speaker: Marco CIRELLI (Laboratoire de Physique Théorique et Hautes Énergies (LPTHE) - CNRS and Sorbonne U., Paris, France)

16.DMcandidates.iDM_Zaragoza.no_backup.pdf

Coffee Break

Parallel Session - Indirect Detection / Astro

Convener: Juande Zornoza (IFIC (Univ. de Valencia - CSIC))

5 Constrains to sub-GeV dark matter interactions with galactic neutrino observations

The IceCube and ANTARES collaborations recently reported measurements of high-energy neutrinos from the galactic plane and galactic ridge. If cosmic rays scatter off dark matter particles at the galactic halo efficiently, a sizable high-energy neutrino flux may be produced. If we consider the deep inelastic scattering of cosmic rays with dark matter particles at the galactic ridge, we can track the resulting high-energy neutrino spectra from meson decays. In this talk I will show how current measurements from ANTARES already allow us to place strong bounds in some regions of the parameter space of sub-GeV dark matter and what is going to be the sensitivity to this interactions that future neutrino experiments can reach.

Speaker: Jorge Terol Calvo (INFN Torino)

IDM 2026 CR-DM -1.pdf

6 The First Flight of the GAPS Antarctic Balloon Mission: Searching for Dark Matter with Cosmic Antinuclei

The nature of dark matter is one of the great open questions in physics. The General Antiparticle Spectrometer (GAPS) experiment is an Antarctic balloon mission optimized specifically for low energy (< 0.25 GeV/n) cosmic antinuclei as uniquely low-background signatures of dark matter. The secondary production of low-energy astrophysical antideuterons is strongly suppressed by the scarcity of high-energy cosmic rays and their relativistic kinematics, which predominantly produce high-energy products. Moreover, cosmic antideuterons have not yet been detected, therefore, any detection of antideuterons by GAPS would represent a potentially groundbreaking discovery. In addition, GAPS will deliver a high-statistics measurement of the antiproton spectrum in the 0.1 and 0.3 GeV/n energy range, below that of any other experiment, and provide unique sensitivity to cosmic antihelium. The GAPS experiment uses a novel exotic-atom-based technique to distinguish cosmic antinuclei from the abundant nuclei background without the need for a magnet. The GAPS payload consists of layers of plastic scintillator panels which make up the time-of-flight system and surround a 10-layer Si(Li) tracker. GAPS flew for the first time this past Antarctic summer, spending over 25 days at float altitude. I will be presenting an overview of the GAPS instrument and of the first flight campaign of GAPS.

Speaker: Kaliroe Pappas (Columbia University)

GAPS_IDM.pdf

7 WIMP Dark Matter Searches from the Galactic Centre with KM3NeT/ORCA

The method of indirect detection of Dark Matter (DM) in neutrino telescopes involves the observation of a Cherenkov light pattern produced by particles crossing the detector that originate from DM annihilation or decay. A signal of neutrinos produced by these processes is searched for in astrophysical targets such as the Galactic Centre or the Sun, where large amounts of DM are believed to accumulate. The KM3NeT infrastructure, located in abyssal sites of the Mediterranean Sea, includes multiple detectors, among which ORCA is optimized for measuring low-energy neutrinos. In its final configuration, ORCA will consist of 115 vertical detection lines, each containing 18 optical modules with 31 photomultiplier tubes that detect light signals. In this contribution we present an analysis with an unbinned likelihood method looking for WIMP-like DM annihilations occurring at the Galactic Centre, where we consider DM with masses ranging from approximately 1 GeV up to 1 TeV. We use various partial ORCA-detector configurations ranging from 6 to 18 lines to explore low masses.

Speaker: Adriana Bariego Quintana (KM3NeT IFIC (CSIC-UV))

IDM - WIMP Dark Matter Searches from the Galactic Centre with KM3NeT-2.pdf

8 Probing Dark Matter in the Galactic Center with CTAO: Sensitivity and Morphology Insights

Due to its proximity and high dark matter (DM) content, the Galactic Center (GC) is one of the preferred targets in the search for WIMP DM. Even in the absence of clear signals, GC observations can be used to set the best DM constraints. Despite the GC being a crowded region, rich in very diverse gamma-ray astrophysical emissions, thanks to both its expected flux and angular sensitivity, the forthcoming Cherenkov Telescope Array Observatory (CTAO) will prove to be the best tool for DM indirect searches in the TeV regime. In this work, we adopt state-of-the-art modeling of the GC astrophysical emission and, focusing on a wide range of cuspy and spiked DM density profile distributions, we show the expected sensitivity of CTAO to a DM annihilation signal within the inner 3.5 degrees of the GC. Furthermore, the template-fitting approach allows us to recover valuable information on the morphology of the DM density distribution in the inner ~500 parsecs of the GC.

Speaker: Jaume Zuriaga-Puig (IFT UAM-CSIC)

IDM_Jaume_ZuriagaPuig.pdf

9 Probing heavy dark matter with the KM3-230213A event

The recently reported KM3-230213A neutrino event, observed with the KM3NeT/ARCA detector, represents the most energetic neutrino observed to date. It has stimulated significant interest in possible explanations of its origin, including those beyond conventional astrophysical scenarios. In this contribution, we investigate whether the event could originate from the decay of a heavy dark matter particle with a mass above the PeV scale. We evaluate the expected signal distributions for several decay channels and determine the regions of dark matter mass and lifetime compatible with the observation. We also assess the relative contributions from galactic and extragalactic dark matter and compare the preferred parameter space with existing limits from neutrino telescopes and gamma-ray observations.

Speaker: Dr Alfonso Garcia-Soto (IFIC)

idm.pdf

10 Detecting light axions from supernovae in nearby galaxies

Axion-like particles (ALPs) coupled to nucleons can be efficiently produced in core-collapse supernovae (SNe) and then, if they couple to photons, convert into gamma rays in cosmic magnetic fields, generating short gamma-ray bursts. Though ALPs from a Galactic SN would induce an intense and easily detectable gamma-ray signal, such events are exceedingly rare. In contrast, a few SNe per year are expected in nearby galaxies within $\sim \mathcal{O}(10)$ Mpc, where strong magnetic fields can enable more efficient ALP–photon conversions than in the Milky Way, offering a promising extragalactic target.
This circumstance motivates full-sky gamma-ray monitoring, ideally combined with deci-hertz gravitational-wave detectors to enable time-triggered searches from nearby galaxies. We show that, under realistic conditions, a decade of coverage could reach sensitivities to ALP-photon coupling $g_{a\gamma} \gtrsim 10^{-16}~{\rm GeV}^{-1}$ for ALP masses $m_a \lesssim 10^{-9}$ eV and assuming an ALP-nucleon coupling close to SN 1987A cooling bound. This sensitivity would allow one to probe a large, currently-unexplored region of the parameter space below the longstanding SN 1987A bound.

Speaker: Francesca Lecce

Nearby galaxies presentation copia.pdf

Parallel Session - Direct Detection

Convener: Claudia Tomei (INFN Sezione di Roma)

11 Commissioning and design of the CYGNO-04 directional detector at LNGS

We present the status of the CYGNO experiment which is now focusing on the development of the new 0.4 m$^3$ underground demonstrator at the Laboratori Nazionali del Gran Sasso (LNGS). CYGNO aims for the development of a large gaseous Time Projection Chamber (TPC) with optical readout, operated with a He:CF$_4$ gas mixture, for directional rare event searches such as neutrino and dark matter searches in both the spin-dependent and spin-independent channels. In the CYGNO experimental approach, primary ionisation charges produced by particle interactions are amplified by a triple Gas Electron Multiplier (GEM), generating visible scintillation light read out by a CMOS-based Active Pixel Sensor and a set of fast Photomultiplier Tubes (PMTs). This approach enables detailed 3D event reconstruction while keeping the sensors outside the sensitive volume, thus reducing background contamination. The design of CYGNO-04 builds on the successful underground operation of the LIME detector, the largest 50 L prototype of the project. The LIME underground campaign at LNGS demonstrated 3D reconstruction capability and strong electron/nuclear recoil discrimination above 20 keV, validating the experimental technique and motivating the scale-up. In this contribution, we focus on the main results achieved by LIME and on the current construction status of CYGNO-04, including the detector design, amplification stage, optical readout system, gas system, electronics and DAQ integration, and infrastructure preparation for underground deployment at LNGS. We will discuss the main technical challenges encountered in scaling up from LIME to CYGNO-04, the adopted solutions, the integration and commissioning plan, and the expected milestones toward full operation. CYGNO-04 is a key step to demonstrate the scalability and performance of the CYGNO technology on a significantly larger active volume.

Speaker: Stefano Piacentini (GSSI && INFN LNGS)

IDM2026_Piacentini.pdf

12 NEWAGE: low background underground experiment for direction-sensitive dark matter search

The sensitivity of the direct dark matter search is being improved by various energy-sensitive experiments such as dual-phase liquid xenon detectors. 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 updated our detector and its gas purification system to reduce RI emission from the detector and gas, respectively. We will present the latest status of the underground direction-sensitive dark matter search experiment and its prospects.

Speaker: Satoshi Higashino (Kobe University)

higashino_IDM2026_20260601.pdf

13 Dark matter detection with atom interferometers

Atom interferometers are a type of quantum sensors that have been identified as a promising technology to conduct research in fundamental physics. At their core, these instruments feature an ensemble of atoms in a quantum superposition of their energy eigenstates, that represent a unique target to probe large unexplored areas of the dark matter parameter space.

In this talk I will first explain the basic concepts of atom interferometry, and then I will discuss how this technology could be used to search for dark matter. After this introduction, I will review the current initiatives to develop atom interferometer experiments for fundamental physics, along with their respective sensitivities to dark matter.

Speaker: Elias Lopez Asamar (Universidad Autonoma de Madrid)

2026_06_01-idm.pdf

14 The Scintillating Bubble Chamber Experiment

The Scintillating Bubble Chamber (SBC) collaboration is developing liquid-noble bubble chambers sensitive to sub-keV nuclear recoils to search for dark matter in the mass range from approximately 1-10 GeV$/c^2$. These detectors extend the excellent electron-recoil insensitivity inherent in Freon-based bubble chambers with the additional ability to veto higher energy neutron backgrounds based on the scintillation signal. The targeted nuclear recoil threshold of 100 eV is made possible by the increased level of superheat attainable in noble liquids while maintaining high electron-recoil insensitivity. In order to verify this reduced threshold, the SBC collaboration is building two functionally identical 10 kg liquid argon detectors. The first, SBC-LAr10, now taking data at Fermilab, will be used for engineering and calibration studies. The second detector, SBC-SNOLAB, will probe the spin-independent dark matter-nucleon cross section down to 10$^{-43}$ cm$^2$ at 1 GeV$/c^2$ with a 10-kg-year exposure. An overview of scintillating liquid-noble bubble chambers, early data from Fermilab, along with the status of SBC-SNOLAB will be presented.

Speaker: Ben Broerman (Queen's University)

Broerman_IDM2026.pdf

15 Exploring Rare Event Searches with the LEGEND experiment: From 0nbb to Dark Matter

The LEGEND Collaboration searches for the neutrinoless double beta (0$\nu\beta\beta$) decay of $^{76}$Ge using high-purity germanium detectors enriched in $^{76}$Ge and deployed within a radiopure liquid argon cryostat.
LEGEND pursues a phased experimental program designed to probe 0$\nu\beta\beta$ decay with a discovery sensitivity in the half-life beyond $10^{28}$ years: LEGEND-200, currently ongoing, and LEGEND-1000, the next generation development.
LEGEND-200 started operating in 2023 at Laboratori Nazionali del Gran Sasso and ran in a stable physics data taking regime for about one year with 142.5 kg of detectors installed.
The performed analysis of LEGEND-200 data finds no evidence for a 0$\nu\beta\beta$ signal. A joint GERDA + MAJORANA Demonstrator + LEGEND-200 analysis provides a limit of $T^{0\nu}_{1/2}$ $>$ 1.9 $\times$ 10$^{26}$ yr, at 90\% CL.
The scientific goals of LEGEND extend well beyond the search for 0$\nu\beta\beta$, covering a wider spectrum of BSM physics, including various dark matter candidates.
In this talk, we will present the performance and the obtained results of the ongoing experiment LEGEND-200, and give an update on the status of its second phase LEGEND-1000. Therefore, we will review the range of dark matter candidates the experiment is well-positioned to probe in both the current and future phases.

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 Canadian NSERC and CFI; the LNGS and SURF facilities.

Speaker: Valentina Biancaccci (GSSI, INFN)

IDM26-Biancacci-LEGEND.pdf

Parallel Session - Theory/Phenomenology

Convener: Manuel Asorey (Universidad de Zaragoza)

16 SUSY Dark Matter Production at the LHC?!

SUSY searches for electroweak (EW) particles at the LHC show consistent excesses between ATLAS and CMS in the channel $pp \to \tilde{\chi}_2^0 \tilde{\chi}_1^\pm \to \tilde{\chi}_1^0 Z^*\,\tilde{\chi}_1^0W^{\pm*}$.
The preferred mass ranges are $m_{\tilde{\chi}_2^0} \sim m_{\tilde{\chi}_1^\pm}$ with $\Delta m := m_{\tilde{\chi}_2^0} - m_{\tilde{\chi}_1^0} \sim 15-20$ GeV. We show that these consistent excesses can be well described within the MSSM and the NMSSM, where the $\tilde{\chi}_1^0$ as DM candidate is in full agreement with all relevant experimental bounds, in particular the DM relic density and the direct detection cross section limits. We discuss how this scenario can be probed at current and future experiments.

Speaker: Sven Heinemeyer (IFT (CSIC, Madrid))

sven.pdf

17 Conversion-Driven Baryogenesis with Quark-Philic Flavored Dark Matter

The origin of dark matter and the baryon asymmetry remains one of the central open problems in fundamental physics. Recent work has shown that lepton-flavored dark matter can naturally realize cogenesis of dark matter and baryons via conversion-driven freeze-out, where semi-efficient dark–visible conversions create a departure from equilibrium while thermalization of the dark sector erases any dependence on initial conditions.
In this talk, we extend this mechanism for the first time to quark-philic flavored dark matter, demonstrating that the viable parameter space is significantly enlarged up to the TeV scale. The enhancement arises from the stronger mediator coupling to quarks and the important role played by QCD bound-state formation during freeze-out. We further analyze the impact of finite-temperature corrections to decay and scattering rates, showing how they modify the thermal history and relic abundance across the parameter space.

Speaker: Lena Rathmann (KIT)

IDM2026_Rathmann.pdf

18 The Dark Matter-Baryon Coincidence: Problem, Solutions, and Signatures

The comparable abundances of dark matter and baryons, known as the dark matter–baryon coincidence, call for an explanation that connects the dark sector to the QCD sector. In this talk, I will present a detailed analysis showing why this coincidence is nontrivial and points toward a strongly coupled dark sector with $\mathcal{O}(1)$-GeV asymmetric dark baryons as dark matter. Based on this insight, we examine the interplay between direct detection experiments and searches for feebly interacting particles, highlighting how these complementary probes can test and distinguish different solutions to the coincidence problem.

Speaker: Yi Chung (Institute for Basic Science)

Yi_Chung_IDM.pdf

19 Beyond 3→2: Towards Realistic SIMP Dark Matter

Strongly interacting dark sectors with pseudo–Nambu–Goldstone bosons provide a versatile framework for sub-GeV dark matter. While the original SIMP paradigm emphasises number-changing $3\to2$ processes as the origin of the relic abundance, the phenomenology of pionic dark matter is considerably richer. Depending on the spectrum and couplings, the relic density can instead be controlled by $2\to2$ annihilations (WIMP-like regime), semi-annihilation channels involving vector mesons and further processes like $\pi\pi\pi\to\pi\rho$. A consistent treatment therefore requires a framework that simultaneously captures pion dynamics, vector mesons, anomalous interactions, and portal effects.
We consider QCD-like dark sectors in which the dark matter candidates are pions stabilized by unbroken dark flavor symmetries. The effective theory is formulated using the Hidden Local Symmetry (HLS) approach. The HLS Lagrangian, supplemented by the gauged Wess–Zumino–Witten term, is constructed in a representation-independent manner and is applicable to complex, real, and pseudo-real fermion theories.
As a minimal benchmark, we focus on the pseudo-real symmetry-breaking pattern $SU(2N_f)/Sp(2N_f)$ with $N_f=2$. We incorporate lattice results for $Sp(N_c=4)$ to obtain realistic relations between $m_\pi/f_\pi$ and $m_\rho/m_\pi$. A dark photon portal is included to maintain thermal equilibrium with the visible sector and to assess its impact on relic abundance and dark matter stability within the HLS framework.

Speaker: Daniil Krichevskiy (University of Stavanger)

Krichevskiy IDM2026 PDF.pdf

20 Wallions: Dark Matter from the Edge of Field Space

We present a new framework (ultra)light dark matter based on a scalar field experiencing boundaries in field space. These boundaries give rise to wallions, excitations whose masses are exponentially suppressed yet radiatively stable. After introducing the basic setup, we will discuss how wallions behave in the early universe, how field-space boundaries can form dynamically, and which probes may be sensitive to them.

Speaker: Mathias Becker (University of Padova)

IDM26.pdf

13:30 Lunch

Parallel Session - Indirect Detection / Astro

Convener: Miguel A. Sanchez Conde (Universidad Autónoma de Madrid (UAM) & Instituto de Física Teórica (IFT UAM-CSIC))

21 Legacy analysis of Milky Way dwarf spheroidal satellite galaxies: an update

Dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are targets of great interest for searches of Dark Matter (DM) signatures with the Fermi-LAT. In the last decade the number of detected and putative dSphs has been rapidly increasing, allowing for some of the most stringent constraints to be put on models of annihilating DM in the GeV-TeV range. The most recent results even highlight the presence of local significance excesses at the 2-3 sigma level. With the recent observations of ultra-faint compact stellar systems (UFCSs), that might be the darkest galaxies ever observed, and the predictions on the upcoming results of the Legacy Survey of Space and Time (LSST), which poses to double or more the sample of known dSphs over the next decade, we stand before a fundamental moment for gamma-ray searches of DM signatures.
In this work, we apply key improvements to the analysis of the dSphs. We use stricter cuts on the data, implement a method to adaptively model the background, and assume an updated framework for DM annihilation. We find that our improved background modeling leads to a better agreement between the model and the data. This produces an increase in the local and global significance of the dSphs excess compared to previous studies. Finally, we find that the DM properties obtained in this work are less dependent on the sample of dSphs being considered, while remaining in agreement with the predictions from the Galactic center excess observed by theFermi- LAT and the antiproton excess observed by the Alpha Magnetic Spectriometer (AMS-02).

Speaker: Antonio Circiello (Clemson University)

idm_2026_circiello.pdf

22 An Exciting Dark Matter Solution to the MeV Galactic Anomalies

In this talk, I will present recent work using MeV Galactic observations to search for dark matter. I will discuss how the long standing 511 keV gamma-ray line, recent 2 MeV in-flight annihilation excess, and anomalous Central Molecular Zone (CMZ) ionisation can be addressed within one model paradigm, "Excited Dark Matter". A brief overview for future experimental prospects will also be covered.

Speaker: Shyam Balaji (King's College London)

IDM_2026_conf_Shyam.pdf

23 Combined Gamma-Ray Constraints on WIMP Dark Matter from Milky Way Dwarf Spheroidal Galaxies

Weakly interacting massive particles (WIMPs) remain a central benchmark for particle dark matter, with gamma-ray observations providing one of the most powerful probes of annihilation signals across a wide mass range. Milky Way dwarf spheroidal galaxies (dSphs) constitute particularly robust targets due to their high dark matter content and low astrophysical foregrounds, enabling sensitive searches with minimal background modeling uncertainties.

We present the final results of a comprehensive multi-instrument analysis combining observations from five major gamma-ray facilities: Fermi-LAT, H.E.S.S., MAGIC, VERITAS, and HAWC. By integrating space- and ground-based datasets covering energies from ~100 MeV to ~100 TeV within a unified likelihood framework, this work achieves unprecedented sensitivity to dark matter annihilation signals in dSphs. The analysis incorporates consistent treatments of statistical and astrophysical uncertainties while preserving the complementary strengths of the individual instruments.

The combined constraints probe WIMP dark matter masses between 5 GeV and 100 TeV and improve upon existing single-experiment limits by factors of approximately 2–3 over significant portions of parameter space. For several benchmark annihilation channels, the resulting bounds approach or surpass canonical thermal relic cross sections, placing some of the most stringent gamma-ray limits on WIMP dark matter to date.

Beyond the immediate implications for particle dark matter, this study demonstrates the scientific reach enabled by coordinated analyses across independent observatories and establishes a methodological framework for future joint searches. These results illustrate the critical role of broad energy coverage and collaborative strategies in advancing indirect dark matter detection in the era of next-generation gamma-ray and multi-messenger experiments.

Speaker: Javier Rico (IFAE-BIST)

JRico_GD_IDM2026.pdf

24 Stellar streams as targets for indirect dark matter searches

In this talk, we summarize our research on stellar streams as a new and complementary target for dark matter (DM) searches with gamma rays.

Stellar streams whose progenitor is a dwarf galaxy (dG) are particularly interesting targets for DM searches, since dGs are thought to be highly DM-dominated systems. We expect these streams to have lost most of their DM content during the stretching process, yet a significant amount of DM should remain within their core. If the DM particles are Weakly Interacting Massive Particles (WIMPs), they could annihilate in the streams’ core, producing a detectable gamma-ray signal. In this work, we analyze data from the Large Area Telescope on board the NASA Fermi satellite (Fermi LAT) to look for a potential WIMP annihilation signal from the direction of an optimized sample of streams. In the absence of a signal, we place the first constraints on the WIMP parameter space obtained from these objects for several annihilation channels.

A key challenge in this analysis is the uncertainty in the DM density profile of the streams, which directly impacts the expected gamma-ray flux. To address this issue, we will also present our ongoing work in which we are using the Auriga suite of high-resolution hydrodynamical simulations to model the DM distribution within disrupted dG streams. These simulations provide a more robust framework for interpreting our results and refining future DM searches with stellar streams.

Speaker: Cristina Fernandez Suarez (Universidad Autónoma de Madrid (UAM) & Instituto de Física Teórica (IFT UAM-CSIC))

IDM2026_Streams_CristinaFernandezSuarez.pdf

25 Probing Dark Photon Dark Matter with CTAO

The dark photon is a new hypothetical gauge boson arising in extensions of the Standard Model, and constitutes a compelling dark matter candidate. As dark photon dark matter (DPDM), it can interact with electromagnetic fields via kinetic mixing, and the inelastic scattering process γγ′ → e+e⁻ becomes kinematically allowed for gamma rays above a characteristic energy threshold. This interaction imprints unique spectral attenuation features at very-high-energies (VHE), offering an observational probe of DPDM models. Using the Cherenkov Telescope Array Observatory (CTAO) Instrument Response Functions (IRFs), we simulate observations of VHE sources and forecast novel sensitivities to the kinetic mixing parameter for the photon–dark photon scattering process. Our study focuses on three key astrophysical targets: the Crab Nebula and the blazars Markarian 421 and Markarian 501. Additionally, we investigate the impact of dark matter spikes around black holes on the upper limits. Our results demonstrate that CTAO can probe the DPDM parameter space down to a mixing parameter of ε ∼ 10⁻⁸ for masses around mDP ∼ 10⁻¹ eV through high-energy spectral attenuation, at a 95% confidence level.

Speaker: Júlia Mamprim (Universidade de São Paulo)

IDM2026_JuliaGMamprim.pdf

Parallel Session - Direct Detection

Convener: Maria Martinez (CAPA - UZ)

26 ANAIS−112: Towards Completing the Model-Independent Test of the DAMA/LIBRA Signal

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, collected data smoothly with excellent performance at the Canfranc Underground Laboratory, Spain, from August 2017 until January 2026, accumulating a total exposure of 900 kg·yr. Results corresponding to a six-year exposure led the international, model-independent effort to test the DAMA/LIBRA signal, showing compatibility with the absence of modulation and incompatibility with DAMA/LIBRA at a sensitivity above 4σ. In this talk, the current status of the experiment and prospects for the upcoming full dataset unblinding will be presented, with the potential to reach a 5σ sensitivity. Systematic effects affecting the comparison will also be discussed, particularly those related to the response of the detectors to nuclear recoils.

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

IDM2026_ANAIS_IvanCoarasa_vdef.pdf

27 Overview and Prospects of COSINE-100U: Upgrade NaI(Tl) Dark Matter Search in Yemilab

COSINE-100 experiment, a direct dark matter search using NaI(Tl) crystal detectors at the Yangyang Underground Laboratory in Korea, completed approximately six years of data taking in March 2023. During this time, COSINE-100 provided valuable insights into various dark matter interpretations such as validating DAMA/LIBRA, search for sub-GeV spin-dependent dark matter search, and exploring other exotic dark matter candidates. The experiment has since been upgraded to COSINE-100U and relocated to Yemilab, a newly established underground laboratory in Jeongseon, Korea.
The upgraded experiment has achieved a significant improvement in detector performance, with an approximately 40% enhancement in light yield, enabled by a newly developed encapsulation technique for the NaI(Tl) crystals. In addition, COSINE-100U aims to further improve its sensitivity by operating the detector at a reduced temperature of −30 °C. With these substantial improvements, the experiment is expected to probe previously unexplored low-mass WIMP dark matter parameter space, particularly for spin-dependent interactions.
The installation of the upgraded detector system has been successfully completed, and data taking began in September 2025. To date, approximately 100 days of room-temperature physics data have been collected, and low-temperature data taking is scheduled to begin in March. In this presentation, we describe the detector design and performance, the analysis strategy including background modeling and event selection, and discuss the projected sensitivity for low-mass spin-dependent WIMP searches.

Speaker: Gyunho Yu (Institute for Basic Science)

cosine100u_idm2026.pdf

28 The SABRE experiment: status and prospects

The SABRE experiment aims to deploy arrays of ultra-low-background NaI(Tl) crystals to carry out a model-independent search for dark matter through the annual modulation signature.
SABRE will be a double-site experiment, consisting of two separate detectors in the two terrestrial hemispheres. The SABRE North detector will be installed underground at LNGS and will deploy an array of 9 ultra-high radio-purity NaI(Tl) detectors (5 kg mass each) in a Cu and PE passive shielding. The expected background rate in the ROI [1,6] keV is of order 0.5 dru. To this end SABRE North will make use of zone refining purification of the NaI powder.
The collaboration has confirmed by means of several tests the technology to produce 5 kg size NaI(Tl) crystals after zone refining purification,
a breakthrough in the production of ultra-high radio-purity NaI(Tl) scintillators. Based on this development SABRE North is starting crystal production. The first crystal after zone refining will be characterised at LNGS in 2026. Results from zone refining runs and crystal growth development will be reported, together with the time schedule of crystal production and detector deployment.

Speaker: Claudia Tomei (INFN Sezione di Roma)

SABRE_Tomei_IDM2026 (1).pdf

29 The SABRE South Experiment at the Stawell Underground Physics Laboratory

SABRE is an international collaboration that will operate similar particle detectors in the Northern (SABRE North) and Southern Hemispheres (SABRE South). This innovative approach aims to distinguish potential dark matter signals from seasonal backgrounds: a pioneering strategy only feasible with a Southern Hemisphere experiment. SABRE South is located at the Stawell Underground Physics Laboratory (SUPL), in regional Victoria, Australia. SUPL is a newly constructed facility situated 1024 metres underground (∼2900 metres water equivalent) within the Stawell Gold Mine. Its construction was completed in 2023.

SABRE South employs ultra-high purity NaI(Tl) crystals immersed in a linear alkyl benzene (LAB)-based liquid scintillator veto, surrounded by passive steel and polyethylene shielding, and topped with a plastic scintillator muon veto. Significant progress has been made in the procurement, testing, and preparation of equipment for the installation of SABRE South. The assembly of the experiment at SUPL will take place this year. The SABRE South muon detector and data acquisition systems are already operational and actively collecting data at SUPL, and full commissioning of SABRE South is planned this year. This presentation will provide an update on the overall progress of the SABRE South construction, its anticipated performance, and its potential physics reach.

Speaker: Leonie Einfalt (The University of Melbourne)

IDM_2026_red.pdf

30 WIMP search results from the full six-year COSINE-100 dataset

The COSINE-100 experiment, situated at the Yangyang underground laboratory, utilizes NaI(Tl) detectors to search for WIMP dark matter and provide a direct, model-independent test of the DAMA/LIBRA annual modulation claim.
While previous model-independent analyses of the full six-year dataset found no evidence of annual modulation, excluding the DAMA/LIBRA signal at a significance greater than 3$\sigma$, this presentation focuses on the model-dependent WIMP extraction results.
Event selection for the full six-year dataset has been completed, and the analysis threshold has been lowered from 0.7 to 0.5 keV. This improvement enables the COSINE-100 experiment to achieve competitive sensitivity to WIMPs with GeV-scale masses.
We present the final WIMP extraction analysis from this full exposure, which excludes the DAMA/LIBRA-favored region for spin-independent interactions and provides world-leading constraints on spin-dependent WIMP–nucleon cross sections for WIMP masses in the 0.1 – 5 GeV/c² range.

Speaker: Jinyoung Kim (Chung-Ang University / Center for underground physics, Institute for basic science (CUP, IBS))

2026IDM_JinyoungKim.pdf

2026IDM_JinyoungKim.pdf

Parallel Session - Theory/Phenomenology

Convener: Sven Heinemeyer (IFT (CSIC, Madrid))

31 Charged Sterile Neutrinos as Dark Matter

The sterile neutrino is a well motivated Dark Matter candidate, but the minimal Dodelson-Widrow production mechanism has been experimentally excluded by searches for X-rays. We are presenting an extension, in which DM consists of sterile neutrinos which are charged under a broken $U(1)'$ symmetry. As long as one sterile neutrino is neutral under $U(1)'$, they will mix with the SM neutrino through a seesaw mechanism. In addition to generating neutrino masses, the mixing will naturally add a channel triggering exponential growth of the Dark Matter abundance in the early universe, through the process $\nu_s \nu_{SM} \to \nu_s \nu_s$. With an initial abundance generated by Dodelson-Widrow, we show that this mechanism opens up the parameter space, in mass and mixing angle, where sterile neutrinos can make up all of the Dark Matter. We also find that the available parameter space is bounded from all sides by limits from DM self-interactions, X-ray and Lyman-$\alpha$ searches.

Speaker: Halvor Melkild (University of Oslo)

Melkild_IDM26.pdf

32 Dark higher-form portals and duality

Among the crowd of dark matter candidates, light scalar (axions, ALPs, WIMPs …) and vector particles (dark photons) have been the focus of intense theoretical and experimental investigations over the past 15 years. However, those are always described as scalar or vector fields. Instead, we investigate their embedding as antisymmetric rank-three and rank-two tensor fields. By reconciling theoretical investigations, regarding the nature of the dualities relating the standard and tensorial descriptions and their different possible Stueckelberg gauge representations, and phenomenological examinations considering the effective interactions between tensor fields and the Standard Model, we prove these tensor fields to provide a completely distinct framework. This alternative set allows for different couplings and therefore different experimental signatures for the detection or production of dark matter at both low energy and colliders.

Based on Dark higher-form portals and duality (ArXiv :2506.04795) and Dark higher-form fields and triangle anomalies (ArXiv:2602.14839)

Speaker: Cypris Plantier (Laboratoire de Physique Subatomique et de Cosmologie (LPSC))

Zaragoza_15_minutes_talk.pdf

33 Combined constraints on dark photons from high-energy collisions, cosmology, and astrophysics

We investigate a dark sector coupled to the Standard Model (SM) via a kinetically mixed dark photon $U$ associated with an additional $U(1)'$ gauge symmetry. The kinetic mixing parameter $\varepsilon$ induces an effective coupling to the electromagnetic current, while interactions with a stable dark matter (DM) particle $\chi$ are governed by a dark gauge coupling $g_\chi$, spanning the four-dimensional parameter space $(m_U,\varepsilon,m_\chi,g_\chi)$. Our study employs the parton--hadron--string dynamics (PHSD) transport approach, extended to model dark-photon production and its dilepton decay channel ($U\to e^+e^-$). Within PHSD, dark photons are generated in high-energy collisions through multiple sources, including Dalitz decays of light mesons ($\pi^0,\eta,\eta',\omega$), $\Delta$-resonance transitions ($\Delta\to N U$), direct vector-meson decays ($\rho,\omega,\phi\to U$), kaon decays ($K^+\to\pi^+U$), and quark--antiquark annihilation ($q\bar q\to U$). Using established PHSD validations against dilepton measurements as a baseline, we derive upper bounds on $\varepsilon^2(m_U,m_\chi,\alpha_\chi)$ in both the visible regime ($m_U<2m_\chi$), where $U\to e^+e^-$ is dominant, and the invisible regime ($m_U>2m_\chi$), where the opening of $U\to\chi\bar\chi$ reduces the dilepton branching ratio. Cosmological and astrophysical information is included in two complementary steps. First, we evaluate the velocity-dependent self-interaction cross section $\sigma/m_\chi$ for Yukawa-mediated self-interacting DM (SIDM) and compare it to constraints from dwarf galaxies, galaxy groups, and clusters. Second, we compute thermal freeze-out target curves by solving for the relic abundance and imposing $\Omega_{\rm DM}h^2\simeq 0.12$, consistent with Planck cosmic-microwave-background determinations. By combining the PHSD-driven limits on $\varepsilon^2$ with relic-density and self-interaction requirements, we delineate excluded regions in the $(m_\chi,m_U)$ plane for different DM realizations (Dirac fermion, Majorana fermion, and complex scalar), and we highlight benchmark scenarios in which heavy-ion, cosmological, and astrophysical constraints can be satisfied simultaneously.

Speaker: Adrian William Romero Jorge (Goethe Frankfurt University/FIAS)

iDM_Romero_Jorge.pdf

34 Gravitational dark matter production, its uncertainties, and its interplay with freeze-in

The persistent absence of non-gravitational dark matter signals has increased interest in candidates that interact extremely weakly with the Standard Model—if at all. (Non-perturbative) gravitational particle production provides an unavoidable mechanism for generating such dark matter via the expansion of spacetime. However, predicting the exact relic abundance is subject to significant theoretical uncertainties arising from the choice of inflationary potential, field spin, and the details of the reheating phase.
In this talk, I will present an estimation of these uncertainties based on recent results for scalar and vector spectator fields across different inflationary backgrounds. Furthermore, I explore the conceptual and technical challenges of reconciling this gravitational production—rooted in QFT in curved spacetimes—with the freeze-in mechanism, typical in astroparticle physics.

Speaker: Álvaro Parra López (University of Oslo)

SlidesIDM_AlvaroParra_WOB.pdf

35 What can flavour tell us about Dark Matter?

The non-trivial flavour structure of t-channel dark matter models with fermion couplings is unavoidably constrained by flavour physics, hinting towards the presence of an underlying flavour symmetry.
In this talk, I present a systematic study of the low-energy flavour constraints affecting these models from the perspective of flavour symmetries, together with complementary bounds from collider searches and dark matter direct detection experiments.
I show that the TeV scale suggested by the freeze-out mechanism is compatible with the various probes only in specific flavour-symmetric limits, highlighting the essential role of flavour symmetries in the realisation of these models.

Speaker: Xavier Ponce Diaz (University of Basek)

XPD_DM_Flavour_IDM.pdf

16:40 Coffee Break

Parallel Session - Cosmology

Convener: Javier Redondo (CAPA, DPTUZ)

36 Light, Warm and Noisy Dark Matter

Light post-inflationary axions are generically warm and noisy, leading to early, scale-dependent structure formation on observationally accessible scales. I will highlight results from a general, multi-species–friendly analytical framework, together with lattice numerical simulations, of such structure formation and its implications. In particular, the absence of both (1) free-streaming–induced small-scale suppression, and (2) Poisson-noise–driven enhancement in the matter power spectrum implies a lower bound on the dark matter mass of 10^(−19) eV.

Speaker: Mustafa Amin (Rice University)

Amin_IDM26.pdf

37 Tracking Dark Matter through Cosmic Magnetism: Can the Footprint of Dark Matter Survive Nonlinear Evolution?

The origin and evolution of cosmological magnetic fields remain open problems with potential implications for physics beyond the standard cosmological model. In particular, several dark matter scenarios predict non-trivial interactions with primordial magnetic fields, either modifying their initial spectrum or imprinting characteristic signatures during structure formation. Assessing whether such imprints can survive subsequent non-linear evolution requires a detailed understanding of magnetic field amplification mechanisms in realistic cosmological environments.

In this contribution, we present ongoing work aimed at disentangling the physical processes responsible for magnetic field amplification in high-resolution cosmological magnetohydrodynamic simulations performed with the MASCLET code. Our approach is based on a decomposition of the magnetic induction equation formulated in an expanding cosmological background, allowing the magnetic energy evolution to be separated into contributions from compression, stretching, advection, and cosmological expansion. This formalism enables a quantitative assessment of how different environments and dynamical regimes reshape the magnetic field over cosmic time.

A central aspect of this analysis is the distinction between compressive amplification and amplification driven by the small-scale dynamo (SSD). While compressive processes tend to amplify the magnetic field without significantly altering its large-scale topology, the SSD powered by turbulent, rotational motions, efficiently redistributes power across scales and can erase memory of initial configurations. To isolate these effects, we combine the induction-based decomposition with the VORTEX code, which performs a Helmholtz decomposition of the velocity field. This allows us to identify the solenoidal (rotational) component of the stretching term that constitutes the physical signature of the SSD.

This framework provides a physically motivated pathway to evaluate whether primordial magnetic signatures potentially linked to dark matter interactions can survive in specific environments where compressive amplification dominates, or whether they are erased by turbulent dynamo action, exploring the viability of using cosmic magnetism as an indirect probe of dark matter physics.

Speaker: Marco José Molina Pradillo (Universitat de València)

Plenary Session HTML This is the HTML version I use for presentations, available upon request. One needs to download it and uncompress it before entering in the folder and clicking on the index.html file to open it as a webpage in the default browser.

Public PDF This is the PDF version of the slides, available to the public

38 The spectrum of axions in a scaling string network

A promising dark matter candidate, which arises from a proposed solution to the strong CP problem is the pseudo scalar axion. If the PQ symmetry is broken after inflation, a network of cosmic strings forms and emits axions until the QCD phase transition, where a hybrid string-wall system forms and collapses. Characterizing both the evolution of the network and the emission of axions by the tangle of strings is crucial for obtaining precise axion mass estimates. Following our previous work where we obtain evidence of standard scaling of axion strings (number of string lengths per Hubble patch asymptotes to a constant), we will present new results from our $12288^3$ simulations, along with new cleaner observables of the axion spectrum, and a novel modeling framework. Consistent with the picture of standard scaling, we observe the emergence of a self-similar axion spectrum, with a form in broad agreement with scale invariant emission by strings.

Speaker: José Ricardo Correia (University of Oslo / Institute of Astrophysics)

IDM2026_June_JRCCCC.pdf

39 Seasons of Dark Matter Freeze-In Shaped by the Weather of the Early Universe

Quantifying the imprints of freeze-in dark matter (DM) on cosmological structures requires the knowledge of its phase-space momentum distribution. We investigate how different cosmological histories before nucleosynthesis, what we refer to as “weather” of that epoch, give rise to distinct “seasons” in the DM momentum distribution that govern its warmness. Studying decay-driven production across diverse cosmological scenarios, we map how these conditions shape DM phase-space properties. Our study quantifies how the early universe composition plays a key role in determining the mass bound on freeze-in DM.

Speaker: Tommaso Sassi (University of Padua, INFN Padua)

Sassi_IDM2026.pdf

Parallel Session - Direct Detection

Convener: Belina von Krosigk (Heidelberg University, Kirchhoff-Institute for Physics)

40 The COSINUS Experiment at LNGS - Commissioning and Start of the first Phase

The upcoming COSINUS experiment will search for dark matter using cryogenic NaI calorimeters with dual-channel readout of the phonon and scintillation light signals. Its first goal is crosschecking the longstanding DAMA/LIBRA dark matter claim with a target exposure of 100kgd. Via the discrimination between nuclear recoil signals and electromagnetic background, COSINUS detectors achieve unique sensitivity for this purpose, and are also able to provide a model-independent test that does not require any assumption on the dark matter spectrum. Prototypes reach a nuclear recoil energy resolution of 150eV, and detector modules will be operated in the underground laboratory of LNGS together with an active water cherenkov muon veto. After successful construction of the facility, commissioning is ongoing, and first detectors are being installed in the pulse tube precooled "dry" dilution cryostat for test runs. In this contribution, we will give an overview on the COSINUS cryogenic facility at LNGS, recent prototype results and an outlook on the physics reach of the experiment and its measurement strategy.

Speaker: Mariano Cababie (TU Wien - Marietta Blau Institute for Particle Physics)

COSINUS@IDM2026.pdf

41 High pileup event reconstruction and single photon statistics in cryogenic scintillating calorimeters

Cryogenic scintillating calorimeters are particle detectors widely used in direct detection dark matter searches. They can measure the full, unquenched recoil energy of an interaction while simultaneously distinguishing nuclear recoils from electron recoils. This is achieved by detecting both the phonon signal and the scintillation light produced in a recoil event. Data analysis of these detectors is often challenged by high pileup rates — especially in above-ground measurements such as the one presented here for a NaI prototype of the COSINUS collaboration. In addition, recent advancements in scintillation light detectors have enabled single-photon resolution, making it necessary to model the light signal using Poisson statistics. This contribution presents a plug-and-play generalized optimum filter approach that allows reliable event triggering and accurate energy reconstruction under high pileup conditions. It also introduces a new statistical model describing recoil event distributions in the (phonon, light)-plane which correctly incorporates single photon statistics.

Speaker: Philipp Schreiner (TU Wien, Marietta Blau Institute for Particle Physics)

2026_06_01_CSC_SCHREINER.pdf

42 Probing dark matter interactions with a RES-NOVA prototype cryogenic detector

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 (CEvNS), 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 CEvNS-based detectors, RES-NOVA may also be capable of observing DM particles from our galactic halo. The detector design, sensitivity, and the first results on a direct search of DM search using a RES-NOVA prototype detector are presented.

Speaker: andrea melchiorre (LNGS-INFN)

IDM2026_andrea_melchiorre.pdf

43 Preparing for First Science: Commissioning and Outlook of SuperCDMS SNOLAB

SuperCDMS SNOLAB is a cryogenic experiment projected to achieve world-leading sensitivity for dark matter masses below 10 GeV/c$^2$ using semiconductor crystal detectors. The experiment employs two detector types - iZIP detectors with combined phonon and charge readout providing excellent nuclear recoil/electron recoil discrimination, and HV detectors which amplify phonon energy proportional to an applied external electric field to achieve lower detection thresholds. Commissioning of the full twenty-four detector payload, comprising both silicon and germanium iZIP and HV detectors, began in early 2026. This talk presents preliminary results from the characterization and commissioning of the full detector payload, along with a first look at early SuperCDMS SNOLAB data. As the experiment prepares to commence its first science run, this talk will also discuss the experimental outlook and ongoing R&D efforts aimed at developing the next generation of low-background detectors for sub-GeV detection.

Speaker: Dr Aditi Pradeep (SLAC)

IDM 2026 SuperCDMS.pdf

Parallel Session - Theory/Phenomenology

Convener: David Cerdeño (IFT UAM-CSIC)

44 Modeling electronic final states in liquid xenon for light dark matter detection

Liquid xenon is an important target material in for the direct detection of light dark matter (DM) via electron recoils. Consequently, accurate modeling of the DM-electron interaction in this medium is crucial. In particular, a proper description of the electron final states plays a key role in modeling the electronic response of the detector. We follow a novel approach in which the final states are described as linear combinations of positive-energy eigenstates of the Schrödinger equation, combined with a DFT modeling of the liquid xenon phase. These states replace the single positive-energy eigenstate approximation commonly adopted when liquid xenon targets are treated as collections of non-interacting atoms. Our approach therefore represents a step towards a more realistic description of liquid xenon as an interacting many-body system. This talk presents preliminary results comparing the existing literature with DM-electron scattering rates obtained with our description of the final states.

Speaker: Theresa Backes (Chalmers University of Technology)

TheresaBackes_IDM2026.pdf

45 Precision Atomic Response Functions for Probing Dark Matter–Electron Scattering in Xenon and Germanium Detectors

This work presents a comprehensive theoretical investigation of dark matter (DM)–electron interactions using atomic response functions (ARFs), with a focus on Germanium and Xenon—two widely employed detectors in direct detection experiments. Accurately modeling these interactions is essential for interpreting and guiding searches for light dark matter candidates, particularly in scenarios where DM particles interact with atomic electrons rather than nuclei.
Our goal is to develop a comprehensive set of ARFs at leading order (LO), derived using state-of-the-art atomic many-body methods. We show that the complex dynamics of DM-induced atomic ionization can be effectively described by four independent atomic response functions. These newly identified responses prove particularly significant in the context of light dark matter (LDM) scenarios, which we investigate using a model-independent effective field theory framework.
To achieve this, we employ the relativistic random-phase approximation (RRPA) and the relativistic frozen-core approximation (RFCA), enabling differential cross-section predictions with estimated accuracies of ~5% (RRPA) and ~20% (RFCA)[1,2, 3].
Using our computed ARFs, we set 90% confidence level exclusion limits on various DM-electron effective interaction operators by comparing with null results from current and ongoing experiments. In particular, our analysis is relevant to the CDEX and CDMSlite experiments, as well as xenon-based detectors such as XENONnT and other next-generation liquid xenon experiments. These detectors, with their increasing sensitivity to low-energy ionization signals, stand to benefit from the improved theoretical modeling provided by our atomic approach.
This study not only refines theoretical tools for interpreting DM-electron signals but also enhances the sensitivity of future searches. The results will be presented at an upcoming international conference.
[1] M. K. Pandey et al., Phys. Rev. D 102, 123025 (2020).
[2] C.-P. Liu et al., Phys. Rev. D 106, 063003 (2022).
[3] C.-P. Liu et al., arXiv:2501.04020.

Speaker: Mukesh Kumar Pandey (Department of Physics, Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei, Taiwan)

46 Sub-GeV dark matter from cosmic ray bremsstrahlung in the atmosphere

The null results in direct detection motivate the exploration of a broader mass range for thermal relic dark matter (DM) candidates.  An intuitive new place to extend these models is to consider masses in the MeV to GeV range.  One way to do this and avoid bounds from the Cosmic Microwave Background is to introduce a dark sector consisting of a dark mediator and stable DM candidate.  

In this project, we explore a way that inelastic cosmic ray collisions can produce a sub-GeV DM candidate with a boosted energy spectrum via proton bremsstrahlung. The production model uses the most recent form factors for dark vector production from initial state radiation including the fitting of resonant structures. The calculation for this production mode is much more similar to an accelerator calculation than other direct detection efforts with the twist of using the cosmic ray spectrum as a varying beam energy. The DM spectrum peaking at higher energies than the galactic halo allows lighter DM candidates to produce significant recoil signals in the detector. In particular, neutrino experiments are more sensitive to these events as the detector recoil energies lie well within the experiment’s higher thresholds. The larger exposure of such experiments gives them more coverage of the phase space for DM models with a dark photon mediator.

This work is soon-to-be published with my supervisor Dr. Adam Ritz and collaborator Dr. Peter Reimitz.

Speaker: Branden Aitken (University of Victoria)

Aitken_IDM2026.pdf

47 Unitarity in the non-relativistic regime and implications for dark matter

Unitarity imposes strict bounds on elastic and inelastic partial-wave cross sections. However, state-of-the-art calculations, motivated by dark-matter phenomenology, can exhibit substantial violations of partial-wave unitarity, with potentially significant consequences for phenomenological predictions.

In this talk, I present a new, model-independent formalism that restores unitarity through the consistent resummation of inelastic contributions to the self-energy of the incoming state. This framework provides a systematic and internally consistent treatment of inelastic effects. I will illustrate its implementation in existing bound-state-formation calculations, demonstrating how unitarity is recovered in regimes where existing calculations break down. The method is broadly applicable and has implications for dark-matter freeze-out, indirect detection, and self-interactions.

Speaker: Marcos Flores (University of Oslo)

mmflores_IDM_2026.pdf

Welcome cocktail

Welcome cocktail.pdf

Tuesday 2 June

Plenary Session

Convener: Nicolao Fornengo (University of Torino and INFN/Torino)

48 Gamma-ray dark matter searches circa 2026: status and future prospects

The nature of dark matter (DM) in the Universe remains one of the greatest mysteries of our time. Searches for annihilation or decay products of DM particle candidates such as WIMPs have already provided stringent constraints on their properties across a wide range of masses and interaction channels. In this review talk, I will summarize the current status of these ‘indirect’ DM searches in gamma rays. I will highlight key targets, current limitations, and the role of systematic uncertainties. I will then discuss future prospects for DM sensitivity with upcoming experiments as well as emerging opportunities for exploring DM signatures in gamma rays.

Speaker: Miguel Sánchez-Conde (Universidad Autónoma de Madrid & IFT UAM-CSIC)

Gammas&DMstatus_masc_IDM2026_020626.pdf

49 Cosmic Rays in the search for Dark Matter

Dark matter constitutes most of the matter content of the Universe, yet its particle nature remains unknown. Charged cosmic rays provide a powerful avenue to search for possible dark matter signatures through anomalous contributions to the observed fluxes of antimatter. In this talk, I will discuss the status of indirect dark matter searches across multiple cosmic-ray channels. After reviewing the main theoretical framework and relevant astrophysical backgrounds, I will present current observational constraints from cosmic-ray measurements and discuss the main associated uncertainties. Finally, I will highlight the potential of cosmic rays to probe dark matter models beyond standard WIMP scenarios.

Speaker: Pedro De la Torre Luque

IDM_DMCRs.pdf

IDM_DMCRs.pptx

50 Searches for dark matter with neutrino telescopes

Speaker: Juande Zornoza (IFIC (Univ. de Valencia - CSIC))

ZaragozaIDM-jun24-DMnutel.pdf

51 Dark Stars in the JWST era

The James Webb Space Telescope is transforming our view of the early universe, revealing a population of unexpected sources at cosmic dawn, including ultra-compact, dust free, extremely luminous “Blue Monsters” and the Balmer-break-dominated “Little Red Dots.” These discoveries, together with the growing evidence for massive black holes at very high redshift, highlight emerging tensions with pre-JWST models for the formation of the first stars and their Black Hole remnants. In this talk, I present a review of the Dark Star paradigm—stars powered by dark matter—and its implications for the formation of the first luminous objects. I will summarize the theoretical foundations of Dark Star formation, their subsequent growth into Supermassive Dark Stars (SMDSs), and the predicted observational signatures that distinguish them from conventional stellar populations. I will then connect these predictions to current JWST observations, discussing how SMDSs may provide a unified framework for interpreting the properties of compact high-redshift sources and for explaining the origin of massive black hole seeds at early times. Finally, I will highlight recent observational developments, including JWST NIRSpec results, that offer emerging support for the presence of Dark Star–like objects in the early Universe.

Speaker: Cosmin ilie

ILIE SMDS IDM 2026.pdf

Coffee Break

Parallel Session - Indirect Detection / Astro

Convener: Pedro De la Torre Luque

52 Probing the neutrino fog with XENONnT: CE$\nu$NS, light WIMPs, and BSM-$\nu$ physics with a 6.77 t$\times$yr exposure

At IDM 2024, the XENON collaboration reported the first indication of nuclear recoils from solar $^{8}$B neutrinos via coherent elastic neutrino-nucleus scattering (CE$\nu$NS) in the XENONnT detector, utilizing a total exposure of 3.51 t$\times$yr from the first two science runs. In this talk, I will present the results of a blind search for CE$\nu$NS using the third science run, which contributes an additional 3.25 t$\times$yr of exposure. I will discuss the combined analysis of these datasets, summarize key improvements in the data analysis pipeline, and present updated results on CE$\nu$NS, searches for light WIMPs, and Beyond Standard Model (BSM) neutrino physics.

Speaker: Giovanni Volta (Max-Planck-Institut für Kernphysik)

slides_idm_26_volta.pdf

53 Dark Recipe for the First Giants: From Population III Stars to Early Supermassive Black Holes via Dark Matter Capture

The presence of supermassive black holes (SMBHs) at high redshifts (z>5), as revealed by James Webb Space Telescope (JWST), challenges standard black hole (BH) formation scenarios. We propose a mechanism in which non-annihilating dark matter (DM) with non-gravitational interactions with the Standard Model (SM) particles accumulates inside Population III (Pop III) stars, inducing their premature collapse into BH seeds having the same mass as the parent star. Owing to their early formation, these seeds can accrete for longer periods and grow into the SMBHs observed at early cosmic times. Focusing on spin-dependent (SD) DM-proton interactions, we identify regions of parameter space that account for the observed high-redshift SMBH population, their mass function, and the SMBH-stellar mass relation. Portions of this parameter space are testable by forthcoming direct detection experiments. The scenario may lead to distinctive gravitational wave (GW) signatures from SMBH mergers, accessible to Laser Interferometer Space Antenna (LISA) and pulsar timing array (PTA) observations.

Speaker: Debajit Bose (Indian Institute of Science (IISc), Bengaluru, India)

Debajit_Bose_IDM2026.pdf

54 Analyzing Fermionic Dark Matter scenarios with anomalous compact objects

In this paper, we consider three compact objects (HESS J1731-347, PSR-J1231, XTE J1814-338) with anomalous mass-radius relation to analyze the possibility of being dark matter admixed neutron stars. We try to infer the dark matter particle properties, under the assumption of behaving as a free Fermi gas. The main novelty relies on the use of a baryonic equation of state obtained from first principles in the whole density range, that allows to eliminate the model dependence of the baryonic part of the calculation. We model the dark matter component as a Free Fermi gas. Once the possible Dark Matter Admixed Neutron Star configurations are obtained, we check their stability and whether it is feasible for a Neutron Star to capture the necessary dark matter fraction. We show that two of the anomalous compact objects (HESS J1731-347 and PSR-J1231) can be explained with a small fraction of fermionic dark matter content in the star. The other compact object (XTE J1814-338) cannot be explained as a dark matter admixed neutron star, and is a potential candidate for a twin star.

Speaker: Yaiza Cano (Universidad de Alcalá de Henares)

Analyzing Fermionic Dark Matter scenarios with anomalous COs.pdf

55 Cosmic-ray antinuclei in dark matter searches: Insights from collider data

Cosmic-ray antinuclei, in particular antideuterons ($\overline{\rm D}$) and antihelion-3 (${}^3\overline{\rm He}$), are among the most promising messengers for indirect dark matter (DM) searches. Their interest arises from the strong suppression of secondary production in cosmic-ray interactions with the interstellar medium at kinetic energies $K\sim 0.1–1$ GeV/n, where the expected astrophysical background lies one to two orders of magnitude below the flux predicted in many DM scenarios. In this context, recent tentative evidence reported by the Alpha Magnetic Spectrometer (AMS-02) for candidate ${}^3\overline{\rm He}$ events—together with a comparable number of $\overline{\rm D}$—would have profound implications for cosmic-ray physics and dark matter searches if confirmed.

A major theoretical uncertainty in interpreting such signals is the formation of antinuclei, typically modeled through phenomenological coalescence prescriptions. We present a study showing that physically motivated coalescence models can simultaneously reproduce collider measurements in two distinct regimes: (anti)deuteron production in $pp$ collisions measured by ALICE at $\sqrt{s}=0.9-13$ TeV and antideuteron multiplicities in hadronic $Z$ decays measured by ALEPH. These results support an approximately universal coalescence scale and provide a robust framework for predicting antinuclei yields.

Within this framework we also investigate a recently proposed Standard Model mechanism for antihelion-3 production via displaced-vertex decays of $\overline{\Lambda}_b^0$ baryons. Using a dedicated PYTHIA tuning consistent with LEP measurements of $b$-quark fragmentation and with ALICE and ALEPH data on $\overline{\rm D}$ and ${}^3\overline{\rm He}$ production, we derive predictions for antinuclei yields from heavy-flavor decays that are compatible with current LHCb limits. We find that the contribution of beauty-hadron decays to ${}^3\overline{\rm He}$ production is subdominant relative to direct hadronization.

Our results strengthen the theoretical basis for interpreting current and upcoming cosmic-ray antinuclei searches, particularly in light of future measurements by AMS-02 and the upcoming GAPS experiment, which will provide unprecedented sensitivity to low-energy antideuterons from dark matter.

Speaker: Jordan Koechler (INFN Turin)

2026_antinuclei_IDM.pdf

56 Spikes in Milky Way X-ray binaries

Dark matter can form very steep density enhancements, or spikes, around black holes. Recent work has proposed that unusually rapid orbital‑period decay observed in two nearby black‑hole X‑ray binaries could be caused by such spikes. If confirmed in systems where current formation models do not predict them, this would imply far more widespread, dense dark‑matter structures than expected. We revisit these claims with N‑body simulations and include a third, previously unexamined system. Our simulations show that feedback effects substantially reshape the spikes, excluding the shallow density profiles suggested earlier; continued long‑term evolution may alter the spike further, underscoring the need for improved models of binaries embedded in dense dark‑matter environments.

Speaker: Francesca Scarcella (Instituto de Fisica de Cantabria)

IDM26_Scarcella.pdf

Parallel Session - Direct Detection

Convener: Roberto Santorelli (CIEMAT)

57 Latest results of the PandaX-4T experiment

The PandaX-4T experiment is a dual-phase liquid xenon time projection chamber operated at the China Jinping Underground Laboratory (CJPL), shielded by approximately 2400 m of rock overburden. The detector contains 4 tonnes of liquid xenon, with a 3.7-tonne fiducial mass optimized for ultra-low background rare-event searches.

Using commissioning and early science data, PandaX-4T has set leading limits on spin-independent WIMP–nucleon elastic scattering, reaching cross-section sensitivities near 10^{-47} cm^2 for WIMP masses around tens of GeV/c^2. The analysis is based on a profile likelihood approach with data-driven background modeling, including intrinsic radioactivity and neutron-induced backgrounds.

In addition, PandaX-4T has reported an indication of solar ^8\mathrm{B} neutrinos via coherent elastic neutrino–nucleus scattering (CEνNS) with a few-sigma significance. This result validates detector response in the sub-keV to few-keV region and marks an important step toward precision neutrino measurements and exploration of the neutrino fog. Parallel studies include rare xenon processes such as double-beta decay.

Speaker: Xiaopeng Zhou (Beihang University)

iDM2026-PandaX4T.pdf

58 DEAP-3600 updates: new physics results and prospects for exotic DM searches

Inelastic Boosted Dark Matter (IBDM) models provide a multi-component dark sector scenario in which a relativistic dark matter state can inelastically scatter off matter producing distinctive electron-recoil like signatures. Unlike canonical WIMP interactions, IBDM events are expected to deposit significantly higher energies and may exhibit two collimated tracks with vertex displacement, depending on the underlying model parameters. Direct detection experiments are optimized for low energy recoils, but are also sensitive to this unconventional signature. DEAP-3600 is an example of such detector, which uses a 3.3 tonne liquid Ar target and has very low background, a highly efficient muon veto and, being installed at SNOLAB, has an extremely low muon flux. These features make it suitable for IBDM searches.

Signal modeling and event selection strategies are being developed to identify characteristic IBDM signatures in DEAP-3600 and suppress backgrounds. Based on these studies, in this talk I plan to address the projected sensitivity of DEAP-3600 to IBDM events over a representative region of model parameter space and compare it with the state of the art.

Speaker: Guillermo Vera Díaz (CIEMAT)

IDM_2026_DEAP3600.pdf

59 New Dark Matter search results from XENONnT with combined science runs

The XENONnT experiment is aiming for the direct detection of dark matter in the form of weakly interacting massive particles (WIMPs) using a dual-phase liquid xenon time projection chamber. The detector, operated at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy, features a total liquid xenon mass of 8.5 tonnes, of which 5.9 tonnes are active. XENONnT has now successfully completed three science runs, achieving and maintaining exceptional levels of radiopurity throughout, with radon activities at the level of O(1) μBq/kg. The experiment has further continuously improved its background rejection capabilities, notably through the addition of gadolinium doping to the water Cherenkov neutron veto, significantly boosting its neutron detection efficiency. The latest results from the XENONnT WIMP search, obtained from the combined analysis of all three science run datasets, will be presented.

Speaker: maxime pierre (Nikhef)

idm2026-maximepierre_v0.pdf

60 Recent results from the LUX-ZEPLIN (LZ) experiment

LUX-ZEPLIN (LZ) is a direct detection dark matter experiment that utilises a dual-phase time projection chamber (TPC) with 7 tonnes of active xenon at the Sanford Underground Research Facility in Lead, South Dakota. The experiment is primarily designed to detect interactions from weakly interacting massive particles (WIMPs), a well-motivated class of dark matter candidate. Following the establishment of the most stringent constraints on WIMP-nucleon scattering for masses between 9 GeV/c2 and 10 TeV/c2, LZ has completed a dedicated search for light dark matter in the 3-9 GeV/c2 mass range. The latter result, giving a world-leading limit at masses above 5 GeV/c2, will be the main focus of this talk. This analysis also includes our recent 4.5-sigma observation of solar ${}^{8}$B neutrinos via coherent elastic neutrino–nucleus scattering (CEνNS), demonstrating the sensitivity of large xenon detectors to keV-scale neutrino interactions and marking an important step toward the neutrino fog regime.

Speaker: Alberto Uson (University of Edinburgh)

LZ results Uson IDM.pdf

61 Status of the DarkSide-20k experiment

The DarkSide-20k experiment has been designed to lead the search for heavy WIMPs. It will consist of a 50 tonne dual-phase Ar TPC, surrounded by a 40 tonne LAr scintillator veto, both filled with underground Ar, strongly depleted in 39Ar. The outermost layer will be a muon veto, with 650 tonnes of atmospheric Ar. The experiment is in construction phase at the Laboratori Nazionali del Gran Sasso (LNGS), with the cryostat already installed and being instrumented as clean room for the last integration steps.

In this talk I will present the physics goals of the experiment, its current status and the plans towards commissioning.

Speaker: Vicente Pesudo Fortes (CIEMAT / LSC)

DS-20k_IDM2026_Zgz_vpf.pdf

62 PandaX-20T: the next generation xenon detector for dark matter and neutrino searches

PandaX (Particle and Astrophysical Xenon experiment), a large-scale liquid xenon dark matter detection project located at the China Jinping Underground Laboratory, has provided a high-sensitivity experimental platform for dark matter and neutrino searches through the iterative development of three generations of detectors since its launch in 2009. To further enhance the sensitivity to these rare signals, PandaX collaboration has proposed a next generation detector PandaX-20T, which is planned to get online in 2027. Over 20 tonnes of xenon will be utilized, resulting in a diameter of ~2m and a height of ~2.5m for the time projection chamber. New R12699 photomultiplier tubes with much lower radioactivity will be employed for photon detection. This talk will give an overview of the status of PandaX-20T R&D and its expected performance.

Speaker: Xiang Xiao (Sun Yat-sen University)

PandaX-20T_XiangXiao_IDM.pdf

Parallel session - Axion searches

Convener: Jaime Ruz (CAPA)

63 Commissioning the Dark Matter Radio 50L Experiment

Dark Matter Radio 50L (DMRadio-50L) is an experiment designed to search for pre-inflationary axion dark matter in the mass range between 20 peV/$c^2$ and 20 neV/$c^2$, corresponding to Compton frequencies between 5 kHz and 5 MHz. This talk presents the current commissioning status of DMRadio-50L, focusing on the performance of the toroidal magnet, lumped-element resonator, and dc SQUID readout. With the full cryogenic system now operational, the experiment is ready to commence data taking.

Speaker: Victoria Ankel (Stanford University)

idm_slides_v1.pdf

64 Update on the ALPHA experiment

The axion is a well-motivated dark matter candidate with a possible mass range spanning many orders of magnitude. Theoretical models have provided strong motivation to search for post-inflationary QCD axions, but this higher mass range is challenging to reach with traditional resonant cavity haloscopes. Among other limitations, scaling the resonant cavity to frequencies in the tens of GHz would greatly reduce signal power and scan rate due to a necessary decrease in cavity volume. To solve this problem, the Axion Longitudinal Plasma HAloscope (ALPHA) experiment will use a metamaterial resonator to reach high search frequencies while maintaining a large volume. In Phase I, ALPHA will search the 10-20 GHz range at KSVZ sensitivities. Construction of this first phase of ALPHA is currently underway at Yale University. This talk will present an update on the experiment construction, subsystem commissioning, and discuss Phase I plans.

Speaker: Samantha Lewis (Wellesley College)

IDM_Lewis2026.pdf

65 First MADMAX searches for axion and dark photon dark matter

The MAgnetized Disk and Mirror Axion eXperiment (MADMAX) is an experiment aiming to detect dark matter axions from the galactic halo by resonant conversion to photons in a strong magnetic field. It uses a novel concept based on a stack of dielectric disks in front of a mirror, called booster, to enhance the potential signal from axion-photon conversion over a significant mass range. In its final version, MADMAX aims to scan the uncharted QCD axion mass range around 100 mu-eV, favoured by post-inflationary theories.
Several small-scale prototype systems have been tested these last three years, allowing to validate the dielectric haloscope concept and perform competitive axion and dark photon dark matter searches. This talk will present the current status of the experiment and its prototypes, including the results achieved so far, the ongoing research and development
and the remaining challenges.

Speakers: Béla Majorovits (MPI für Physik), MADMAX Collaboration (MADMAX)

IDM_2026_madmax_260512.pdf

66 An axion search using a dielectric Fabry-Perot cavity and trapped electron single photon counter

The axion is a particle which solves the strong CP problem and is a well-motivated candidate for dark matter. The Quantum Enhanced Particle Astrophysics (QuEPA) project at Imperial College London looks to detect axions with masses in the 124-248 µeV range (Compton frequencies 30-60 GHz). Towards this goal, a dielectric Fabry-Perot cavity has been developed to convert axions to microwave photons. Fabry-Perot cavities offer volume factors with more favourable scaling with axion frequency compared to traditional cylindrical cavities. A first-generation axion converter has been constructed and tested under cryogenic conditions. High quality factors have been measured and a first scientific run is under developed.
To circumvent the standard quantum noise limit, which severely hampers higher mass axion searches [1], we are also developing a single-photon counter based on an electron in a Penning Trap [2]. We have trapped small clouds of electrons and are working towards coherent control of a single trapped electron, in preparation for demonstrating the photon counting methods.
[1] S. K. Lamoreaux et al., Phys. Rev. D 88, 035020 (2013) https://doi.org /10.1103/PhysRevD.88.035020
[2] J. A. Devlin et. Al., arXiv:2601.05472, https://doi.org/10.48550/arXiv.2601.05472.

Speaker: Jonathan Gosling (Imperial College London)

An axion search using a dielectric Fabry-Perot cavity and trapped electron single photon counter.pdf

67 Enhancing High-frequency axion searches with quantum sensors at RADES

The search for axions has motivated a wide variety of experimental approaches exploiting the rich phenomenology of this hypothetical particle. Originally proposed as a solution to the strong CP problem in QCD, the axion is also a well-motivated dark matter candidate. The RADES collaboration aims to detect relic galactic axions using haloscopes through the Primakoff effect, whereby axions convert into photons in the presence of a strong magnetic field.
The DarkQuantum ERC Synergy Grant, within the RADES framework, targets two axion mass windows: 1–2 µeV and 30–80 µeV, corresponding to frequency ranges of 200–500 MHz and 8–18 GHz. A key innovation of DarkQuantum at high frequencies is the development of quantum sensors capable of surpassing the Standard Quantum Limit, which constrains traditional power measurements in haloscopes. This approach builds on recent demonstrations of single-photon detection in the microwave regime.
Within RADES, two complementary quantum haloscope concepts are under development: a photon-counting haloscope to measure axion-induced photons in the conversion cavity, and an interferometric haloscope sensitive to axion-induced phase shifts. Both approaches face the challenge of operating quantum devices in strong magnetic fields.
To address this, granular aluminium superconducting devices are being investigated in the collaboration due to their resilience to moderate magnetic fields. In this talk, the high-frequency strategy of the collaboration will be presented, together with the most recent experimental results and ongoing developments toward quantum-enhanced axion searches.

Speakers: David Díez Ibáñez (Laboratoire de Physique de l'École Normale Supérieure (LPENS), París), David Díez Ibáñez (Laboratoire de Physique de l'École Normale Supérieure (LPENS), París)

IDM26_RadesHF_DDI.pdf

68 QUAX Ferromagnetic haloscope read out by a Single Microwave Photon Counter

The search for axions, light and weakly interacting dark matter particles, is nowadays mostly exploited through photon coupling in the sub-meV region. In this range, only haloscopes have a sensitivity to test theoretically motivated axion models.
(talk by Di Vora for the last updates on the QUAX haloscope)

Axions can also be exploited through coupling to fermions, but no experiment is able to reach the required sensitivity in the sub-meV mass range to this date.

Recently, Single Microwave Photon Detectors (SMPDs), chips comprised of two resonators coupled to a superconducting qubit, have been demonstrated to increase the sensitivity to axion signals in a haloscope. The SMPD resolution is a single microwave photon, which allows them to overcome the so-called Standard Quantum Limits of linear amplifiers.

This novel improvement is now being implemented on a ferromagnetic haloscope to further enhance the sensitivity to axions through coupling to the electron. The hypothetical axion signal will excite the magnon mode of a ferromagnetic material (YIG in our case) inserted inside the haloscope cavity. Under the condition of strong coupling, the hybrid mode polariton-magnon can be picked up and read out with the SMPD.

The axion mass tuning is performed by varying the magnetic field acting on the ferromagnetic material. The range to be probed, from $7.2$ to $7.4$\,GHz, will also test the ability to downscale such haloscopes.

Speaker: Giosuè Sardo Infirri

SardoInfirri_QUAX_IDM2026_def.pdf

13:30 Lunch

Parallel Session - Instrumentation for DM searches

Convener: Laura Segui Iglesia (CAPA, Universidad de Zaragoza)

69 First demonstration of the superconducting quasiparticle amplifying transmon (SQUAT) detector architecture for THz/meV sensing

In several proposed dark matter direct detection experiments, microwave photons in the THz/meV range are incident on a focal plane of detectors sensitive to single energy deposition events. Although various types of sensors have been proposed, none have yet demonstrated the ability to resolve single THz photon or meV phonon events across a wide bandwidth. The superconducting quasiparticle amplifying transmon (SQUAT) is a new detector architecture based on a weakly charge-sensitive transmon qubit directly coupled to a transmission line. In the SQUAT, a meV-scale (THz) event breaks Cooper pairs in the qubit’s capacitor islands, generating quasiparticles which then tunnel across the Josephson junction and produce a measurable signal in the qubit’s parity switching rate. Importantly, the SQUAT is not coupled to a readout resonator, allowing for a much higher pixel density on chip and continuous high-bandwidth measurement. Here, we discuss the design and first characterization results of SQUATs and their application to future axion dark matter experiments, particularly BREAD.

Speaker: Alex Droster (Stanford University/SLAC National Laboratory)

IDM2026_droster (2).pdf

70 Calibration of Graphene-based Josephson Junction Detector for Dark Matter Search

Graphene-based Josephson junction detectors are a promising platform for detecting low-energy events, leveraging graphene’s exceptionally low electron heat capacity, intrinsically weak electron–phonon coupling, and the strong temperature dependence of the junction switching current [1]. Recently, we proposed a new strategy for detecting ultra-light dark matter with masses as low as 0.1 keV using graphene-based Josephson junction detectors [2]. In this work, we introduce a detector calibration method that utilizes microwave pulses of varying amplitude for detection efficiency and dark count probability. Using this method, we experimentally quantify the detector performance as a function of deposited energy: the threshold energy is 10.5 meV with a dark count rate of 1670 cps, and at 36.4 meV we achieve a detection efficiency of 95% with a dark count rate of 3×10⁻³ cps. This calibration technique enables the precise determination of the mass range of dark matter that the detector can detect. In addition, the thermal relaxation time of graphene was also quantitatively analyzed with the time-resolved two-pulse experiment. From the time-resolved two-pulse measurement, we extract a thermal relaxation time of 18.5 ns. This provides information on thermal properties of graphene at low-temperature, which is valuable for optimizing detector performance.

[1] E. D. Walsh et al., Phys. Rev. Appl. 8, 024022 (2017); G.-H. Lee, Nature 586, 42 (2020); R. Kokkoniemi, Nature 586, 47 (2020).
[2] D. Kim et al., Phys. Rev. D 112, 015002 (2025).

Speaker: SEUNGHAN LEE (POSTECH)

260525_IDM2026.pdf

71 Understanding quasiparticle dynamics in a superconducting qubit through phonon burst-induced correlated errors

When an ionizing particle interacts with the substrate of a superconducting qubit chip, it generates high-energy athermal phonons that propagate through the material, breaking Cooper pairs in the superconducting films and inducing quasiparticle poisoning. These non-equilibrium quasiparticles limit qubit coherence times and introduce correlated errors across large qubit arrays, posing a major challenge for the development of fault-tolerant quantum computers. At the same time, the potential sensitivity of superconducting qubits to Cooper pair breaking makes them promising detectors for dark matter and coherent elastic neutrino–nucleus scattering, given the meV-scale energy required for quasiparticle generation in most superconductors. In this work, we present a detailed statistical analysis of radiation-induced relaxation errors aimed at modeling the time evolution of quasiparticle density dynamics. From experimental data on five ground-plane transmon qubits, we extract the quasiparticle recombination constant with a precision of ≤10%. Furthermore, we investigate the correlation between the linear loss rate and the energy deposited in the qubit island. Finally, we introduce a statistical reconstruction method based on position localization to estimate the total energy deposited on the chip, providing a pathway toward using superconducting qubits as sensitive particle detectors.

Speaker: Emanuela Celi (Northwestern University)

IDM_CELI.pdf

72 Low-Frequency Axion Searches with Near-Quantum-Limited SQUID Amplifiers: Towards a RADES experiment in BabyIAXO

The search for axions remains one of the most compelling frontiers in particle physics, offering a simultaneous solution to the strong CP problem and the nature of dark matter. Under the framework of the RADES collaboration, the DarkQuantum ERC Synergy Grant is spearheading a transformative approach to axion detection by integrating superconducting quantum technologies into haloscope experiments. While high-frequency searches focus on photon counting, the DarkQuantum Low-Frequency (DQLF) program targets the 1-2 ueV mass range (200-500 MHz). At these frequencies, the primary challenge lies in the large cavity dimensions and large magnets required, and the noise limits of traditional amplification.
To address these challenges, the collaboration is currently constructing a first-generation prototype based on an about 1 m resonant cavity, already capable of reaching discovery-level sensitivity in the 1-2 ueV region. This prototype will serve as a testbed for quantum-enhanced detection technologies and for the development of large-volume haloscopes targeting sub-GHz axion masses. Measurements in the M1 magnet experiment at CERN are foreseen during the third long shutdown (LS3) of the CERN accelerator complex.
A cornerstone of the DQLF strategy is the implementation of quantum-limited linear amplifier detector (QLAD) chain, based on SQUIDs amplifiers. The use of SQUID, combined with high-quality factor superconducting cavities resilient to magnetic fields (such as those based on Niobium Titanium) aims to increase the sensitivity by orders of magnitude. The experience gained in the commissioning and operation of the M1 experiment will be instrumental for the next generation of large-scale haloscopes to be deployed in BabyIAXO.
In this contribution, we present the current status of the DQLF program, the construction of the prototype system, and the integration of quantum sensors, and outline the roadmap toward high-sensitivity searches for galactic axions, including the potential deployment of the experiment in the M1 magnet at CERN during LS3.

Speaker: Dr Jose María García Barceló (Universidad de Zaragoza)

Slides_IDM2026_JMGB.pdf

73 Search for keV-Scale Sterile Neutrinos and Generalized Neutrino Interactions in Tritium β Decay with the LiFE-SNS Experiment

Precision measurements of the tritium β-decay spectrum provide a powerful and model-independent probe of physics beyond the Standard Model. In particular, keV-scale sterile neutrinos are well-motivated warm dark matter candidates that would induce a characteristic kink-like distortion in the β spectrum. Furthermore, generalized neutrino interactions (GNIs) within a dimension-6 effective field theory framework can modify the spectral shape across a broad energy range via additional scalar, vector, and tensor couplings.

The LiFE-SNS project performs a calorimetric measurement of the full tritium β-decay spectrum using neutron-irradiated LiF crystals with embedded tritium, read out by a cryogenic metallic magnetic calorimeter (MMC) operated at millikelvin temperatures. This approach provides high energy resolution and high detection efficiency across the entire β-energy range, enabling sensitivity to both localized and global spectral distortions. In this work we report new constraints on sterile neutrinos in the 10 keV mass range from the first 10-day dataset of the Phase-I operation.

The measured spectrum is compared with a detailed theoretical model that incorporates detector response and analysis effects. Spectral fits are performed to search for the characteristic signatures induced by keV-scale sterile neutrinos as well as spectral distortions predicted by GNIs. These first results demonstrate the feasibility and performance of the LiFE-SNS experimental approach and establish the analysis framework for the full Phase-I dataset and future higher-statistics measurements.

Speaker: Kyung-Rae Woo (Institute for Basic Science in Korea)

2026IDM_sterile_krwoo.pdf

74 Leveraging Quantum Sensors for Dark Matter Detection

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

Speaker: Daniel Baxter (Fermi National Accelerator Laboratory)

idm_060226.pdf

75 The hunt for high frequency gravitational waves — GravNet: a global network of HFGW detectors

A new window to the universe was opened up with the detection of
gravitational waves. While observations have been made at frequencies
around hundreds of Herz, and evidence was found at nHz frequencies, the
high frequency region is still unexplored experimentally. To change this
the GravNet initiative was founded with the aim to setup a global
network of high frequency gravitational wave detectors.
The idea of searching for gravitational waves using radio frequency
cavities immersed in strong magnetic fields has recently received
significant attention. In particular, cavities with rather small volumes
that are currently used to search for axion-like particles are
discussed in this context. The first three detector of the GravNet
network are under construction employing RF-cavities. Several sources of high-frequency gravitational waves are discussed in new physics models, most prominently primordial black hole mergers and axion superradiance, each of which involves dark matter candidates. These production mechanisms produce signals with distinct features. Challenges of detecting gravitational waves from both exemplary sources are discussed as well as prospects for the detection of GW using the network of RF cavity based detectors.

Speaker: Kristof Schmieden (University of Bonn)

2026-06-03_Gravnet_IDM2026.pdf

Parallel Session - Direct Detection

Convener: David Cerdeño (IFT-UAM/CSIC)

76 The Underground Argon program of the Global Argon Dark Matter Collaboration

The DarkSide-20k experiment, under construction the Laboratori Nazionali del Gran Sasso (LNGS), has been designed to lead the search for heavy WIMPs. While liquid argon provides powerful pulse-shape discrimination, the intrinsic cosmogenic Ar-39 in atmospheric Ar (~0.96 Bq/kg) makes multi-tonne Ar TPC experiments for rare-event searches unfeasible.

To address this, and following the successful experience of DarkSide-50, DarkSide-20k will use underground Ar (UAr), which is depleted in Ar-39 by a factor of at least 1400. The Global Argon Dark Matter Collaboration has launched a program to procure and process underground argon (UAr) at industrial scale.

In this talk, I will present the three infrastructures that program relies on and their status: (i) UAr extraction at the Urania plant (Colorado, USA); (ii) isotopic purification in the ARIA distillation column (Sardinia, Italy); and (iii) characterization using the DArT-in-ArDM setup. Particular emphasis will be placed on the latter facility, which recently started commissioning at the Canfranc Underground Laboratory in Spain. I will present the first results and the sensitivity studies performed with actual data.

Speaker: Daniel Díaz Mairena (CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas))

IDM_UAr .pdf

77 Constraining Environmental Backgrounds for Rare Event Searches with LZ

LUX-ZEPLIN (LZ) is the world’s most sensitive direct dark matter detector. It is located deep underground at the 4850 ft level at the Sanford Underground Research Facility in Lead, South Dakota. This is a quiet environment, strongly shielded from cosmic rays. LZ utilises 7 tonnes of liquid xenon in a time projection chamber as a target, primarily searching for weakly interacting massive particle dark matter, but is also sensitive to a plethora of new physics models and rare processes. As with all rare event searches, LZ requires a complete and thorough understanding of all backgrounds, including those induced by the environment of the experiment: external gamma-rays, neutrons and radon. The LZ Environmental Monitoring Station (EMS) consists of a suite of detectors which measure and characterise these key backgrounds. In this talk I will introduce the EMS, highlight the benefits of a permanent in-situ environmental monitoring system for rare event experiments and present the constraints EMS data has placed on key LZ backgrounds.

Speaker: Ellie Bishop (University of Edinburgh)

E Bishop - IDM 26 - final.pdf

78 XLZD – the next generation of dark matter search

Liquid-xenon based dark matter experiments have rapidly increased in size and sensitivity in recent years. They are at the forefront of the search for dark matter interactions with nuclei for dark matter masses above a few GeV/c². XLZD is the next step for this technology and combines the strengths of the XENON, LUX-ZEPLIN and DARWIN collaborations to construct a definitive experiment that can probe the entire accessible WIMP parameter space above the neutrino fog. XLZD will also perform a globally competitive neutrinoless double-beta decay search and be sensitive to a wide variety of other science. I will talk about the scientific goals of XLZD as well as the status of R&D and experimental design.

Speaker: Adam Softley-Brown (University of Sheffield)

IDM26_XLZD_SoftleyBrown.pdf

79 Cryogenic SiPM readout of a NaI(Tl) dark matter detectors within the ASTAROTH project

The direct detection of particle dark matter through nuclear recoils at the keV scale remains a primary objective of underground experiments worldwide. NaI(Tl) scintillators are of particular interest due to their long-standing role in the search for an annual modulation signal, as reported by the DAMA/LIBRA experiment at the Gran Sasso National Laboratory, which still lacks an independent confirmation. Achieving lower energy thresholds and improved light collection is crucial to fully probe the relevant parameter space.

The ASTAROTH project, developed in Milan, aims to advance this field by operating NaI(Tl) crystals in a cryogenic environment and implementing, for the first time, a light readout based on large-area silicon photomultiplier (SiPM) arrays. This innovative approach is designed to overcome limitations of current-generation detectors, with the goal of lowering the energy threshold and extending sensitivity to sub-keV nuclear recoils, where a sizable fraction of the expected dark matter signal may reside.

In 2025, the first successful cryogenic data-taking campaigns were carried out at the LASA laboratory, coupling different SiPM matrices to a NaI(Tl) crystal inside a dedicated cryostat. In this contribution, we present the detector performance achieved so far and outline the developments foreseen for the second phase of the project in the coming years.

Speaker: Davide D'Angelo (INFN - Milano)

IDM_2026_astaroth.pdf

80 The ANAIS+ project: development of scintillation detectors in the 100K temperature range for dark matter searches

The application of NaI and CsI scintillating crystals in dark matter searches suffers from limited sensitivity in the parameter space of WIMP searches despite their high light yield, simple detector design, availability of large-mass crystals, and interesting combination of different target nuclei. Main drawbacks are the high intrinsic background and the difficulty to lower the threshold below 1 keVee.

The ANAIS+ project aims to reduce significantly the energy threshold respect to ANAIS-112 while improving the radiopurity of the crystals and the background rejection strategy. This way, we expect to get an important increase in sensitivity, making ANAIS+ competitive in the searches for low-mass WIMPs with spin-dependent interactions, but also interesting for the study of coherent elastic neutrino-nucleus scattering.

The basis of the project relies on the replacement of the PMTs, classically used to read the scintillation light, by SiPMs operating at temperatures around 100 K. The higher quantum efficiency of these devices, combined with the increased light yield of pure crystals at low temperatures could result in a significant reduction of the energy threshold. On the other hand, changes in other optical properties, like the emission spectrum or the scintillation time, are also under study as they could be a key factor for the design and optimization of a future experiment. ANAIS+ is built as a collaboration between University of Zaragoza, LNGS and CIEMAT. Different prototypes using NaI and CsI have been tested as well as the feasibility of operating them inside a LAr tank that can be used as a thermal bath for the detector and an active 4pi veto. In this talk the status and prospects of the ANAIS+ project will be presented.

Speaker: Jaime Apilluelo Allué (CAPA, Universidad de Zaragoza)

ANAIS+ IDM 2026.pdf

Parallel session - Axion searches

Convener: Béla Majorovits (MPI für Physik)

81 Spontaneous Cogenesis with QCD axion in Type I Seesaw

We propose a generic axion--driven cogenesis scenario in which both the baryon asymmetry and dark matter abundance originate from the kinetic misalignment. The framework unifies the Peccei--Quinn (PQ) mechanism with a Type--I seesaw sector, where Hubble--induced masses and higher-dimensional PQ--violating operators drive early--time axion rotation. Working within the DFSZ axion model augmented by heavy neutrinos, we identify the parametric window of right-handed neutrino masses, determined by its decay rate, and the range of Hubble scales compatible with successful cogenesis, while maintaining the axion solution to the strong CP problem and satisfying current limits on axion isocurvature perturbations. Our results establish kinetic axion misalignment as a robust and predictive mechanism for axion cogenesis, independent of the inflationary microphysics.

Speaker: EUNG JIN CHUN (Korea Institute for Advanced Study)

260602 IDM2026 Cogenesis.pdf

82 New wideband constraints on both hidden photon dark matter at far-infrared wavelengths, and 10-keV scale light dark matter

The QUAntum LImited PHotons In the Dark Experiment (QUALIPHIDE) is primarily a search for hidden photon dark matter. Our far-infrared variant uses an array of single O(THz) photon counting Microwave Kinetic Inductance Detectors coupled to a metallic dish. The presence of on-and-off focus pixels allows for the construction of a data-driven background model and thus results in an experiment with true dark matter discovery potential. With wideband sensitivity in the ~3–120 THz frequency range (hidden photon masses of 13-500 meV c$^{-2}$), and using data from a day-long exposure, we present results from a blinded search for hidden photons and provide constraints on the kinetic mixing parameter $\chi$ down to the 10$^{-12}$ level within the majority of this range. We also report on a search for nuclear/electronic recoil events directly scattering within the small volume superconducting sensors, likely yielding the first ever terrestrial constraints on certain light O(10) keVc$^{-2}$ dark matter species.

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

Ramanathan_IDM_QUALIPHIDE_2026.pdf

83 Searches for dark sectors with the SBND experiment

The Short-Baseline Near Detector (SBND) is a 112-ton liquid argon time projection chamber 110 m away from the Booster Neutrino Beam (BNB) target at Fermilab (Illinois, USA). The close location to the BNB origin makes the experiment sensitive to physics beyond the Standard Model (BSM) produced in the beam. Thanks to its advanced scintillation light detection system, a timing resolution at the nanosecond level further boosts the experiment capabilities.
In this talk, we present the status of searches and expected sensitivities for dark sector particles produced in the decay of mesons and in proton-target interactions in the BNB. We focus on dark photons generated in neutral meson decays and through proton bremsstrahlung, with detection via their visible $e^+e^−$ decay channel, as well as on heavy QCD axions produced through neutral meson mixing and probed in the di-photon final state.

Speaker: Gaetano Fricano (University of Palermo, Fermi National Accelerator Laboratory, INFN)

gfricano_IDM2026.pdf

84 Search for Dark Matter candidates with CUPID-0

CUPID-0 was a pilot experiment in scintillating cryogenic calorimetry designed to search for neutrinoless double beta decay. An array of 26 ZnSe crystals coupled to bolometric light detectors was operated continuously for two years. CUPID-0 demonstrated full $\alpha$ to $\beta/\gamma$ background discrimination, set the most stringent limit on the neutrinoless double beta decay of $^{82}$Se, and achieved the most precise measurement of the $^{82}$Se two-neutrino double beta decay half-life to date.
The excellent energy resolution, particle identification capability, and low background levels achieved with this technology make it exceptionally well suited to rare-event searches of various kinds, including dark matter candidates. We developed background reconstruction techniques to search for sterile neutrino emission through spectral shape distortions in double beta decay of $^{82}$Se, and for solar axions via continuous exotic spectra predicted for interactions with the detector.
In this contribution, we report the latest results from the first search for dark matter candidates using the CUPID-0 technology, demonstrating the effectiveness of scintillating cryogenic calorimeters in the hunt for dark matter and exotic double beta decay modes.

Speaker: Sylvie Pietrarota (La Sapienza Università di Roma, INFN Roma)

IDM_Pietrarota.pdf

85 Unlocking the CUORE keV Frontier: Axion and Rare-Event Searches

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 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 in the CUORE crystals. By applying specialized data selection and noise rejection techniques to over 2 tonne·yr TeO2 exposure, we demonstrate effective event reconstruction at the keV-scale. We quantify the detector performance across the array, exploring how cryogenic conditions, vibrational isolation, and sensor properties influence sensitivity at low energies. These findings validate the use of ton-scale cryogenic calorimeters as broad-range rare event detectors, spanning from the keV to the MeV scale. In this contribution, we present recently published and new results on CUORE's potential for keV-scale energy physics—including searches for axion and WIMP interactions and rare nuclear decays.

Speaker: Anastasiia Shaikina (GSSI)

Shaikina_IDM2026_final.pdf

16:45 Coffee break

Parallel Session - Instrumentation for DM searches

Convener: Grzegorz Zuzel (Jagiellonian University)

86 Towards an International Radon Network for Dark Matter Experiments

Radon remains one of the most limiting backgrounds in direct detection dark matter searches. Major collaborations have made substantial progress in radon detection and mitigation. However, much of the foundational data underpinning radon removal efficiency, material emanation rates, diffusion coefficients, and suppression performance remains experiment-specific. Measurements are often performed under laboratory-dependent conditions, making results difficult to compare directly and systematic uncertainties difficult to propagate.

We propose the formation of an International Radon Network to connect dark matter collaborations and radon-related projects. Building upon decades of foundational work from the University of Sheffield and the Centre de Physique des Particules de Marseille (CPPM), including activities such as the ANR funded IRENE (Innovative mateRials for Extreme radoN capture) project, the network will deliver two core outcomes. First, it will standardise experimental methodologies through common performance metrics and coordinated inter laboratory round robin campaigns. Second, it will establish a shared, structured database of existing and planned radon adsorption, diffusion, emanation, and suppression studies, with standard reporting of experimental conditions. This will enable meaningful cross comparison, inform design decisions, and support sourcing of radon removal media.

The recently established DREAMR (Detecting Radon Emanation and Mitigating Radon) radon facility at the Australian National University provides a timely opportunity to pilot cross laboratory measurements, develop shared reference resources, and host the network database hub. By bringing laboratories and collaborations together such as CPPM's Radon platform, this initiative aims to reduce duplicated effort, strengthen radon control strategies for next generation detectors, and accelerate progress towards the ultimate sensitivity goals of dark matter experiments.

Speaker: Robert Renz Marcelo Gregorio (Australian National University)

RadonRob_IDM2026_v4.pdf

87 Bedretto: A New Underground Laboratory for Fundamental Physics

Deep underground low-background laboratories are critical infrastructure for dark matter experiments and rare event physics searches. With real-estate in short supply, we are establishing a new underground laboratory in Tichinio, Switzerland. With 4000 meters water equivalent overburden, the Bedretto Lab has amongst the lowest cosmic ray fluxes in the world. The radiogenic backgrounds from muons, gamma-rays, neutrons, and radon have all been characterized. Seismic and electromagnetic noise were extensively studied. The Bedretto Lab will be amongst the lowest noise and lowest background laboratories in the world. We propose three immediate use cases: technology demonstrators for the upcoming XLZD experiment, hosting cryogenic low-mass dark matter experiments, and installation of an atomic interferometer sensitive to both gravitational waves as well as wave-like dark matter.

Speaker: Alexander Kavner (University of Zurich)

Kavner-Bedretto-IDM-2026.pdf

88 The Modane Underground Laboratory

The Modane Underground Laboratory is the deepest tunnel-access underground laboratory in Europe. The experimental site is protected by a 4800 m.w.e. overburden that reduce the muon flux to 5 muons/m2/day, and is thus ideal for a wide range of applications requiring ultra-low radioactivity levels. I will present the evolution of this facility and of its science program in the domain of dark matter, neutrinoless double-beta decay and interdisciplinary sciences.

Speaker: Silvia Scorza (LPSC - CNRS)

LSM_IDM2026_Scorza.pdf

89 Mapping Environmental γ-Ray Flux at LNGS: Toward a Systematic Framework for Underground Laboratories

The next generation of rare-event search experiments in underground laboratories requires a precise understanding of all background sources, including environmental γ-ray radiation within experimental halls.
In this contribution, we present recent measurements of the environmental γ-ray flux at the Gran Sasso National Laboratory (LNGS). A dedicated campaign has been carried out using a high-purity germanium (HPGe) detector deployed at multiple locations in Hall C, enabling the first detailed spatial mapping of the γ radiation field in this environment. The measurement approach and the associated simulation framework used to derive the γ-ray flux will be described. In addition, the temporal evolution of the γ-ray rate has been studied in correlation with ambient radon activity, showing a clear dependence consistent with the contribution from short-lived radon progeny. These observations highlight the importance of combined and continuous monitoring of environmental parameters and provide key insight into time-dependent background variations relevant for rare-event searches.
This work is part of a broader effort aimed at a systematic characterization of environmental radioactivity at LNGS, with the long-term goal of extending this program to other underground laboratories to enable consistent cross-comparisons of environmental γ-ray fluxes using a common and calibrated measurement approach.

Speaker: Ludovico Luzzi (University of California Davis)

luzzi_hall_c_gamma_measurement_v2.pdf

90 Boulby Underground Laboratory: Projects and plans at the UK's deep underground science facility

Boulby Underground Laboratory is the UK's deep underground science lab, located in the North East of England. Initially created to host dark matter direct detection experiments, the lab has since expanded into a multidisciplinary facility hosting a wide variety of projects, while continuing to maintain close connections with the dark matter community. As well as hosting a range of dark matter projects, Boulby also maintains a material assay suite which provides a variety of radioassay methods used for screening components for dark matter detectors across the world, including the upcoming next generation LXe detector, XLZD. I will present an overview of our current facility and the dark matter and related projects we host there, and then go on to talk about plans for our new facility and the opportunities for hosting future experiments at Boulby Underground Laboratory.

Speaker: Alice Hamer (Boulby Underground Laboratory)

IDM 2026 Boulby Underground Laboratory.pdf

Parallel Session - Direct Detection / Light DM

Convener: Gloria Luzón Marco (CAPA, Universidad de Zaragoza (ES))

91 DAMIC-M analysis results from the LBC

The DAMIC-M (DArk Matter In CCDs at Modane) experiment is scheduled to begin operations at the Modane underground laboratory (LSM) in late 2026. This talk presents the current status of the project, highlighting recent results from its prototype—the Low-Background Chamber (LBC). Data from the LBC have been used to exclude theoretical benchmarks where hidden-sector particles make up the dominant component of dark matter via freeze-in or freeze-out mechanisms.
We will present its latest results including the daily modulation and solar reflected analysis.

Speaker: Nuria Castello-Mor (IFCA (CSIC-UC))

NCastelloMor_DAMICM_IDM2026.pdf

92 Latest Results and Prospects of the SENSEI experiment.

SENSEI (Sub-Electron Noise Skipper Experimental Instrument) is the first experiment to implement the Skipper-CCD technology in particular to search for light dark matter.. These sensors have single electron resolution in millions of pixels, which when coupled with the small band gap of silicon enables these detectors to be uniquely sensitive to DM-electron scattering processes. SENSEI has recently measured the lowest-ever single electron rates in silicon detectors, resulting in world-leading sensitivity. SENSEI also has performed an analysis searching for earth-scattering induced diurnal modulation, further improving sensitivity near 1 MeV. In this talk we present our latest results from two science runs at SNOLAB, our daily modulation result from the most recent science run at MINOS, and future prospects for SENSEI and other Skipper-CCD detectors.

Speaker: Ansh Desai (University of Oregon)

2026_SENSEI_IDM.pdf

93 The DAMIC-M experiment: an Skipper CCD detector at LSM

DAMIC-M (DArk Matter in CCDs at Modane) is an ongoing direct detection dark matter (DM) experiment located at the Modane Underground Laboratory (LSM). The extremely low energy threshold of Skipper CCDs enables the exploration of previously inaccessible regions of the DM parameter space, particularly for MeV-scale particles interacting with electrons through a U(1) mediator.
Construction of DAMIC-M will begin in summer 2026. In this talk, we will present ongoing efforts to install approximately 300 g of sensitive detectors. We will also report on the current status of underground testing and characterization of the CCD detector modules, aimed at validating stable performance across a large array of devices. These results provide important benchmarks for detector response under low-background conditions, inform calibration and optimization strategies, and demonstrate readiness for scaling up to the full DAMIC-M array.

Speaker: rocio vilar (IFCA)

IDM_DAMICM_2026.pdf

94 Pioneering Sub-GeV Dark Matter Limits with COSINE-100

We report new constraints on the spin-dependent (SD) dark matter (DM)-proton cross section using the COSINE-100 experiment at the Yangyang Underground Laboratory.
By implementing a specialized event selection including Multi-Layer Perceptron (MLP) training, this analysis achieves a detection threshold of 3- and 4-pulse clusters corresponding to the few photoelectrons. This allows us to access the unstudied few-photoelectron regime, significantly below the previous 8-photoelectron threshold.
Using four years of stable data, we find no statistically significant evidence of annual modulation. Consequently, we establish the world's most stringent SD DM-proton constraints for NaI(Tl) in the $1.75–2.25$ GeV/$c^2$ mass range. By incorporating the Migdal effect, we further extend our sensitivity into the $15–58$ MeV/$c^2$ mass range, setting new world-leading limits. These results demonstrate the unique capability of NaI(Tl) targets to probe previously unexplored regions of the dark matter parameter space.

Speaker: Won Kyung Kim (University of Science & Technology (UST), IBS School)

IDM_lowmassDMCOSINE.pdf

95 Results from the MIGDAL experiment

Many dark matter experiments are exploiting the Migdal effect, a rare atomic process, to improve sensitivity to low-mass WIMP-like dark matter candidates. Following the recent first observation of the Migdal effect in nuclear scattering [1] the characterisation of the effect and measurements of the cross-section in a range of elements is of great importance to the DM community. The MIGDAL experiment [2] aims to characterise the Migdal Effect in a range of species and test theoretical predictions of the cross-section. This is performed using a low-pressure optical time projection chamber to image in 3-dimensions the characteristic of a Migdal event: an electron and a nuclear recoil track sharing a common vertex. Nuclear recoils are induced using fast neutrons from a DD source, which scatter in the gaseous volume of the detector. The experiment is operated with 50 Torr of CF4 using two glass GEMs for charge amplification. Both scintillation light and ionisation charge are read-out, and these measurements are combined for full-track reconstruction. In this talk we will present the results of the analysis of the first search for the Migdal Effect in nuclear scattering of carbon and fluorine from the MIGDAL experiment at the Neutron Irradiation Laboratory for Electronics (NILE) at the Rutherford Appleton Laboratory in the UK.

[1] Yi, D., Liu, Q., Chen, S. et al. Direct observation of the Migdal effect induced by neutron bombardment. Nature 649, 580–583 (2026). https://doi.org/10.1038/s41586-025-09918-8

[2] MIGDAL, Astropart.Phys. 151 (2023) 102853. 10.1016/j.astropartphys.2023.102853

Speaker: Lex Millins

IDM2026_final_millins.pdf

96 Probing Sub-GeV Dark Matter via Migdal-Induced Electron Excitations

The electron ionization channel of the Migdal effect in dark matter-nucleus scattering has been shown to enhance sensitivity to sub-GeV dark matter. In this work, we demonstrate for the first time that lower energy electron excitations can also provide a novel and promising pathway, enabling detection of even lighter dark matter previously inaccessible to direct searches. Direct detection experiments based on superfluid $^4$He can exploit this channel by observing electronic excitations via UV-photon emission. We calculate the resulting event rates and find that the electron excitation induced by the Migdal effect can probe dark matter-nucleus scattering for dark matter masses as small as a few MeV.

Speaker: Dr Liangliang Su (Karlsruhe Institute of Technology (KIT))

IDM2026_LiangliangSu.pdf

Parallel session - Axion searches

Convener: Manuel Meyer (University of Southern Denmark)

97 Searching for Solar WISPs with Annual Modulation in ANAIS-112

ANAIS-112 is a dark matter direct detection experiment utilizing sodium-iodide scintillating crystal detectors which was mounted to search for the annual modulation signal expected from dark matter in the Galactic Halo. Located in Canfranc Underground Laboratory in Spain, the experiment has published results which are consistent with no modulation. This strategy, however, may be expanded to search for modulation signals expected from solar particles. As the modulation would peak on January 3rd, when the Earth is closest to the Sun, the signal from solar particle events can be distinguished from other sources by fixing the modulation phase. This presentation explains the interaction channels sodium-iodide detectors would be sensitive to and presents preliminary results of our search for solar axions and solar dark photons which are consistent with no modulation from which exclusion limits are computed.

Speaker: Sophia Hollick (Universidad de Zaragoza)

HollickIDM2026.pdf

98 Solar Axion Searches with BabyIAXO

The International Axion Observatory (IAXO) is a next-generation axion helioscope designed to search for solar axions and axion-like particles (ALPs) with unprecedented sensitivity. The experiment combines a dedicated superconducting dipole magnet with precision X-ray optics and ultra-low background detectors. BabyIAXO will represent the initial stage of the project, serving both as a technological demonstrator for IAXO and as a standalone experiment with significant physics reach. It is expected to provide competitive sensitivity to axion–photon couplings down to g$_{aγ}$ ∼ 10$^{-11}$ GeV$^{-1}$. Beyond solar axion searches, its physics potential includes searches for dark matter axions with haloscopes, supernova axions and other WISPs such as hidden photons and chameleons.

A crucial element of the experiment is the development of detectors capable of achieving extremely low background levels while maintaining high efficiency in the keV energy range. The baseline detection technology for BabyIAXO consists of gaseous Time Projection Chambers equipped with radiopure Microbulk Micromegas. These detectors provide sub-millimeter spatial resolution and good energy resolution, enabling effective background discrimination to reach levels below 10$^{−7}$ counts/keV/cm²/s. In addition, other detection technologies are being explored to address different physics scenarios, including haloscope cavities for dark matter axion searches and liquid scintillator detectors for supernova axions.

Speaker: Ana Quintana García

IDM_2026_BabyIAXO_AnaQuintana.pdf

99 X-ray Telescopes for Axion Searches

X-ray telescopes have become powerful tools in the search for weakly interacting slim particles (WISPs), in particular QCD axions and axion-like particles (ALPs). Through the Primakoff effect, astrophysical magnetic fields can induce axion-photon conversion, giving X-ray observatories unique sensitivity over a broad axion-mass range. This talk reviews recent progress in ALPs searches with NASA's NuSTAR, the first and currently only focusing hard X-ray space telescope. First, observations of the starburst galaxy M82 yield stringent constraints on heavy decaying ALPs in the 30-500 keV range, probing axion-photon couplings in previously unexplored regions of parameter space. Second, NuSTAR observations of the red supergiant Betelgeuse set new and competitive limits on axion-nucleon couplings for masses below the neV, exploiting axion production via nuclear transitions in stellar interiors. Together, these results improve upon earlier astrophysical bounds and motivate future X-ray space missions such as Athena and AXIS, which are expected to extend sensitivity to even fainter axion signatures.

Speaker: Francisco Rodríguez Candón (Universidad de Zaragoza)

IDM_Zaragoza_FRC.pdf

100 Dark matter Axion search with riNg Cavity Experiment (DANCE): Simultaneous resonance for sensitive broadband axion search

Axions and axion-like particles (ALPs) can couple to photons, and many searches have been conducted utilizing the Primakoff effect, which induces axion-photon conversion under magnetic fields. Recently, novel experiments using the interaction between axions and laser photons without magnetic fields have been proposed and are currently underway. These experiments aim to search for ALPs directly by using optical cavities to amplify and detect the rotation of linearly polarized light induced by the axion-photon interaction. We have proposed Dark matter Axion search with riNg Cavity Experiment (DANCE), which employs a bow-tie ring cavity composed of four mirrors to detect the amplified polarization rotation angle. In order to conduct a sensitive broadband search, the incident s-polarization and p-polarization generated by the polarization rotation need to be resonant in the cavity simultaneously. However, our first observation revealed that both s- and p-polarizations were not resonant in the cavity due to oblique incidence on the mirrors, degrading the sensitivity over a wide range of axion masses. By employing a novel method utilizing zero phase shift mirrors and a wavelength tunable laser, we have successfully demonstrated the simultaneous resonance of s- and p-polarizations. We report on the latest sensitivity and future prospects.

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

20260602_IDM2026_Takidera_v3.pdf

101 Polarimetric Searches for Axion Dark Matter with Optical Cavities

Axions are among the most compelling dark matter candidates, motivating the development of precision laboratory searches based on their coupling to photons. In this talk, I will discuss a polarimetric approach to axion dark matter detection using optical cavities, focusing on the birefringence induced by an oscillating axion background in laser polarization. Within this framework, axion dark matter behaves as an effectively circularly birefringent medium, leading to a small rotation of the polarization state that can be resonantly enhanced in high-finesse cavities. I will present sensitivity projections for cavity configurations inspired by ALPS II and show how resonant enhancement, cavity design, and quarter-wave-plate configurations broaden the experimental reach. I will also briefly mention the extension of this method to high-frequency gravitational-wave searches. Based on Phys.Rev.D 112 (2025) 2, 023031

Speaker: Camilo Garcia Cely (IFIC (CSIC-UV))

IDM2026_GarciaCely.pdf

Wednesday 3 June

Plenary Session

Convener: David Cerdeño (IFT-UAM/CSIC)

102 Direct observation of MIGDAL effect in neutron-induced low-energy nuclear recoils

Speaker: qian liu

MARVEL-20260603-IDM.pdf

103 Direct searches for light dark matter with cryogenic experiments

Speaker: Belina von Krosigk (Heidelberg University, Kirchhoff-Institute for Physics)

20260603_IDM-Zaragoza_BvKrosigk.pdf

104 Review of Dark Matter Direct Searches with Argon

Speaker: Roberto Santorelli (CIEMAT)

Santorelli_IDM2026_v2.pptx

105 Review of WIMP searches with liquid Xenon detectors

Speaker: Richard Gaitskell (Brown University)

IDM2026 - Xe Dark Matter Status (Gaitskell) 260603v42.pdf

IDM2026 - Xe Dark Matter Status (Gaitskell) 260603v42.pptx

Coffee Break

Plenary Session

Convener: Igor García Irastorza (Centro de Astropartículas y Física de Altas Energías (CAPA) - Universidad de Zaragoza)

106 Axion astrophysics: bounds and discovery opportunities

Stars have been recognized as optimal laboratories to probe axion properties. In the last decades there have been significant advances in this field due to a better modelling of stellar systems and accurate observational data. In this talk I review the current status of constraints on axions from stellar physics and present the future perspectives. The focus is i on the Sun, globular cluster stars, white dwarfs and (proto)-neutron stars.

https://cern.zoom.us/j/62219760813?pwd=cgiDpf7DPkV3kmb9xVTqvTV1p1a7kX.1

Speaker: Alessandro Mirizzi

axion_IDM.pdf

107 Review of Experimental Axion Searches

A half a century after its prediction, the axion continues to elude either detection or exclusion owing both to its extraordinarily weak couplings and its still largely unconstrained mass. Inspired detection strategies and dramatic advances in technology, particularly in quantum sensing however provide optimism for discovery of the axion or axion-like particles within the next few years. This talk with review the state of dark matter, solar and laboratory searches for the axion, along with the emerging field of observational axion searches. The review concludes with a prospectus of what may be expected after the axion is found.

Speaker: Karl van Bibber (University of California Berkeley)

IDM XVI Talk - KvB.pdf

108 Quantum Sensing and Information Processing for High Energy Physics

Speaker: Aaron Chou (Fermilab)

achou_idm2026.pptx

109 Primordial Black Holes as dark matter

Speaker: Florian Kühnel (Max Planck Institute for Physics)

Kuhnel, Florian - IDM - Zargoza - June 2026 - 3.pdf

Lunch

Parallel Session - Instrumentation for DM searches

Convener: Vicente Pesudo Fortes (CIEMAT / LSC)

110 The semiconductor technology for the Tesseract direct dark matter search experiment at LSM

The search for dark matter has broadened to include low-mass candidates, motivating the development of detectors with extremely high sensitivities and low energy thresholds. The TESSERACT (Transition Edge Sensors with Sub-eV Resolution And Cryogenic Targets) experiment is designed to meet this challenge by deploying ultra-low-threshold cryogenic detectors combined with multiple target materials, providing sensitivity to a wide range of dark matter interactions.
The TESSERACT experiment includes three detector technologies: superfluid helium, polar crystal, and germanium/silicon bolometers. All detectors will operate at a temperature of 10 mK and will be equipped with Transition Edge Sensors (TES) for phonon signal readout. The full TESSERACT experiment setup is scheduled to be integrated at the Modane Underground Laboratory (LSM) in 2028.
This talk will focus on the french Ge/Si semiconductor technology, the R&D progress and their performances.

Speaker: Juliette Blé (LPSC - Grenoble)

IDM2026_TESSERACTGe_BLE.pdf

111 Towards the DELight Experiment: First Results from a Superfluid Helium R&D Cell

The low-mass region of the dark matter (DM) parameter space remains largely unexplored, as detecting Light Dark Matter (LDM) requires both nuclear recoil thresholds below 100 eV and an approach capable of large exposures. The Direct search Experiment for Light dark matter (DELight) aims to address this challenge by using superfluid helium-4 as a target material, exploiting its low nuclear mass, intrinsic radiopurity, as well as its dual photon and quasiparticle signal channels. Detection will be performed using Large-Area Cryogenic Microcalorimeters (LAMCALs). The latter are athermal detectors based on Magnetic Microcalorimeter (MMC) technology which offer excellent energy resolution and detection thresholds of a few eV.
As a first step in this direction, a dedicated R&D cell has been developed to study the operation of thermal MMCs fabricated on a 5 mm × 5 mm silicon substrate, submerged in superfluid helium. In this setup, a small copper cell (300 ml) is cooled down to ~10 mK inside a ³He/⁴He dilution refrigerator and filled with ⁴He. The primary goal is to establish stable MMC operation in this environment, while also beginning to explore the signal channels relevant for DELight, namely the detection of UV photons and of quasiparticles in the superfluid. This contribution presents the current status and recent developments of this R&D cell.

Speaker: Anna Bertolini (Heidelberg University)

Delight_Bertolini_IDM26.pdf

112 Towards ultra-low backgrounds for high-efficiency transition edge sensors in optical and infrared axion searches

Cryogenic transition edge sensors (TESs) are single photon detectors featuring excellent energy resolution below 10% and high quantum efficiency at optical and near-infrared wavelengths. If black-body backgrounds can be suppressed to sufficiently low levels, such detectors would be ideally suited for experiments searching for photon-axion conversion at these wavelengths such as light-shining-through-a-wall (LSW) experiments, axion interferometers, or axion haloscopes. Here, we report on the determination of the system detection efficiency of the TES considered for a potential future run of the Any Light Particle Search II (ALPS II) LSW experiment. With our latest experimental setup, we are able to achieve a system detection efficiency of 86% and milli Hertz background rates. Furthermore, we report on a novel cold optical filter bench that could enable ultra-low backgrounds (below $10^{-7}$ Hz) while maintaining good detection efficiency. The filter bench can be auto-aligned within the cryostat and first results indicate a signal transmission of $\gtrsim$ 60%.

Speaker: Manuel Meyer (University of Southern Denmark)

MMeyer_TES_IDM2026.pdf

113 Technology advances in the SuperCDMS HVeV program

The SuperCDMS HVeV program is an ongoing R&D effort to develop low energy threshold detectors for low-mass (sub-GeV) dark matter searches. The program focuses on gram-scale detectors, with the joint goals of probing new parameter space, and improving our understanding of phonon dynamics and low energy backgrounds in these detectors to inform the next generation of larger scale detectors. These sensors have achieved sub-eV resolution, and by exploiting the Neganov–Trofimov–Luke (NTL) effect, single electron resolution in Si.
We present progress in two avenues of ongoing development and characterization – position-dependent mapping of phonon collection in these detectors, and implementing these detectors on a variety of substrates, with a focus on carbon-based materials. By taking advantage of a steerable cryogenic mirror system, we illuminate the backside of the detectors with sub-mm positional accuracy, enabling us to measure the response to phonons emitted from different areas of the detector surface. Using this approach, we can deduce the detector’s position-dependent phonon collection efficiency and take steps toward position reconstruction of arbitrary events within the detector. In this talk we will show our latest results characterizing these detectors with this tool.
Carbon based target materials present themselves as attractive substrates for these low-threshold detectors. Carbon’s low nuclear mass provides a better kinematic match for low-mass dark matter candidates, and diamond’s high speed of sound and long phonon lifetime have been shown to enhance phonon collection efficiency, further improving detector sensitivity. In this talk, we present results from our characterization of these detectors.

Speaker: Aviv Simchony (Stanford)

IDM talk (2).pdf

IDM talk (2).pptx

114 Development of Cryogenic Single-Photon Detectors to Study the Light Output of Sodium Iodide Crystals for Rare Event Searches

In collaboration between the Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches (COSINUS)—a dual-channel dark-matter direct-detection experiment employing sodium iodide (NaI) as target material—and the Observatory for Neutrino and Dark Matter Electron Scattering (OνDES) project, we developed a cryogenic scintillating calorimeter that enables photon-number-resolved measurements of scintillation light from NaI. The detector module comprises a NaI crystal with a remote Transition Edge Sensor (remoTES) for phonon readout, complemented by multiple silicon light absorbers instrumented with Transition Edge Sensors (TESs) to detect the scintillation signal. The improved light resolution is achieved by using several small silicon absorbers rather than a single large light detector; the reduced heat capacity enhances sensitivity and enables lower detection thresholds. This capability allows a precise characterization of the scintillation light yield of ultrapure NaI crystals, an essential input for the analysis of forthcoming COSINUS data. Moreover, the demonstrated technology provides the basis for future studies of dark matter-electron interactions within OνDES. This contribution presents the detector design and results from a prototype measurement.

Speaker: Lutz Ziegele (Max-Planck-Institut für Physik)

Lutz_Ziegele_IDM26.pdf

Parallel Session - Direct Detection / Light DM

Convener: rocio vilar (IFCA)

115 Searching for light dark matter with DarkSPHERE

DarkSPHERE is a next generation spherical proportional counter to explore light dark matter candidates in the 0.05 - 10 GeV mass range. To maximise radiopurity, the detector is planned to be fully electroformed underground at the Boulby Underground Laboratory. This approach opens up the potential to achieve sensitivity reaching the neutrino fog in the 1 GeV region. In this talk, current efforts towards DarkSPHERE will be discussed, including the commissioning of a high-purity copper electroforming facility in Boulby, and the preparation for a 30 cm in diameter version of DarkSPHERE that could probe new parameter space in this mass region. The expected DarkSPHERE sensitivity for a set of EFT operators is also presented.

Speaker: Dr Lachlan Milligan (University of Birmingham)

IDM2026DarkSPHERELMilligan.pdf

116 Search for low-mass dark matter with NEWS-G

The NEWS-G experiment searches for low-mass dark matter using spherical proportional counters (SPCs), a detector technology combining ultra-low energy thresholds with scalable target masses. In an SPC, ionization produced by particle interactions in a gaseous target drifts toward a central high-voltage anode, where amplification in a strong radial electric field allows for the detection of single electrons.
The latest NEWS-G detector, S-140, consists of a 140-cm-diameter ultra-radiopure copper sphere operated underground. A first physics campaign at the Laboratoire Souterrain de Modane (LSM), using methane gas, yielded world-leading constraints on spin-dependent WIMP–proton interactions in the sub-GeV mass range. The detector is now operating at SNOLAB with light noble gases, including neon and helium, to further extend sensitivity to lower-mass dark matter.
Operations at both LSM and SNOLAB have highlighted key experimental challenges in detector characterization, background mitigation, and event discrimination, motivating the development of new analysis and calibration techniques to maximize SPC performance.
This contribution will present the NEWS-G experimental program, the latest results from the LSM campaign, and recent progress in detector operation and data analysis at SNOLAB.

Speaker: Guillaume Giroux (Queen's University)

NEWS-G_IDM_2026.pdf

117 Low-mass WIMP search challenges with the TREX-DM experiment.

The TREX-DM experiment is a high-pressure gaseous Time Projection Chamber (TPC), located at Canfranc Underground Laboratory (LSC, 2500 m.w.e.), conceived to search for low-mass WIMPs (m < 10 GeV/c2) using novel radiopure Micromegas detectors. In order to be competitive in this low-mass region, TREX-DM faces the challenges of very low background level (order 1 c/keV/day/kg), low energy threshold (typically < 1 keVee) and the optimisation of the gas mixture used (lighter mixtures are preferred). A description of the detector specifications is discussed along with the latest improvements of the experiment and the current status of the high-pressure data taking campaigns. The successful introduction of a GEM as a preamplification stage have already demonstrated the TREX-DM potential to go down to the single-electron ionisation detection. This low energy threshold allows to reach sensitivities in an unexplored low mass WIMP parameter space.

Speaker: Álvaro Ezquerro Sastre (Universidad de Zaragoza)

TREX-DM_IDM2026_AlvaroEzquerro.pdf

118 Rare Event Searches in the Electron Recoil Channel of the XENONnT Experiment

The XENONnT experiment utilizes a dual‑phase liquid xenon (LXe) time projection chamber (TPC) to search for dark matter and other rare events. In addition to its primary nuclear-recoil (NR) search channel, XENONnT has achieved unprecedentedly low background rates in the electron-recoil (ER) channel. With extensive mitigation and active reduction efforts, the dominant ER background from radon and krypton has been reduced to levels comparable to the non-shieldable background induced by proton–proton (pp) chain solar neutrinos, effectively entering the irreducible neutrino background regime. This low ER background allows competitive probes of solar axions, axion‑like particles, and dark photons as dark matter candidates. The talk will summarize the key techniques that enabled this performance, including the cryogenic distillation column that reduced the krypton level below 100 ppq in Science Run 0 and the continuous removal system that reached an order of 1 $\mu$Bq/kg radon level in Science Run 1. The talk will also cover the high-precision measurement methods of the ultra‑low backgrounds in the TPC, including the Rare Gas Mass Spectrometer (RGMS) for $^{Nat}$Kr and dedicated alpha analysis on radon calibrations for $^{222}$Rn/$^{220}$Rn. Finally, this talk will report the latest XENONnT results on ER dark matter channels, on rare event channels from other Standard/Beyond-Standard Model signals, as well as on solar neutrino interaction measurements.

This work is supported by BMFTR under project number 05A23PM1.

Speaker: Dr Ying-Ting Lin (University of Münster, Institute for Nuclear physics)

IDM_2026_YingTingLin.pdf

IDM_2026_YingTingLin.pptx

119 DELight: Direct search Experiment for Light dark matter with superfluid helium-4

The Direct search Experiment for Light dark matter (DELight) aims at combining the scalability of noble liquid detectors, currently setting the strongest limits on heavy Dark Matter (DM) candidates, and the low energy threshold of solid state detectors, with energy resolutions of the order of 1 eV. These properties are combined with an increased recoil signal coming from the choice of a very light target such as helium. These requirements are essential to tackle the largely unexplored parameter space of sub-GeV candidates DM candidates, typically referred to as Light Dark Matter (LDM).

DELight employs a superfluid helium-4 target instrumented with Large Area MicroCALorimeters (LAMCALs), based on Magnetic MicroCalorimeter (MMC) technology. Superfluid helium offers a scalable target with low nuclear mass, ideal for LDM searches, while also providing both photon and quasiparticle signals, enabling discrimination between interaction types and further reducing backgrounds. The LAMCALs achieve a 1 eV energy resolution, necessary to reach a 20 eV threshold in the first phase of DELight. With an exposure of just 1 kg·day, DELight will probe new regions of the parameter space, achieving sensitivities below 10⁻³⁹ cm² at a LDM mass of 200 MeV/c². We will present the working principle of the DELight experiment and an overview of the latest progress towards its realization.

Speaker: Francesco Toschi (Kirchhoff-Institut für Physik, Heidelberg Universität)

IDM2026_Toschi_DELight.pdf

Parallel Session - Theory/Phenomenology

Convener: Sven Heinemeyer (IFT (CSIC, Madrid))

120 Sub-GeV Dark Matter Searches at Spallation Neutron Sources

Sub-GeV dark matter interacting with the Standard Model through vector mediators is well motivated but remains challenging for conventional direct detection experiments. We study the sensitivity of future coherent elastic neutrino–nucleus scattering experiments at spallation neutron sources to light dark matter produced in neutral pion decays. We consider scalar dark matter interacting through a dark photon or a baryophilic vector mediator, with neutral pion production modeled using GEANT4 simulations.
We show that upcoming low-threshold detectors at ESS, J-PARC, and CSNS can probe previously unexplored parameter space, strengthening the search for hidden-sector dark matter.

Speaker: Dimitrios Papoulias (University of Hamburg)

IDM_2026_Papoulias.pdf

121 Interactions of relativistic dark matter with nuclei and implications for light dark matter detection

Direct detection experiments traditionally search for nuclear recoils induced by coherent elastic scattering of halo dark matter particles. This mechanism, however, becomes inefficient for sub-GeV dark matter unless the particles are boosted by astrophysical processes or some other mechanism. In this contribution, we point out that accelerated dark matter interacts with nuclei not only via coherent elastic scattering, but also through inelastic channels, including scattering off individual nucleons and partons, which can produce detectable signatures in neutrino experiments. We discuss the theoretical challenges in consistently describing these processes and demonstrate that their inclusion is essential for realistic sensitivity estimates. As a case study, we consider the cosmic-ray up-scattered dark matter and show that accounting for inelastic scattering significantly impacts the projected reach of the upcoming DUNE neutrino experiment.

Speaker: Helena Kolesova (University of Stavanger)

IDM_Kolesova.pdf

122 Turning background into signal: solar neutrinos in xenon dark matter detectors

Beyond the primary objective of discovering dark matter, direct detection experiments are rapidly emerging as highly effective tools for the study of neutrinos, acting as competitive probes of low-energy interactions with both nuclei and electrons. The XENONnT and PandaX-4T collaborations have recently reported the first evidence of coherent elastic neutrino–nucleus scattering (CEνNS) from solar $^8B$ neutrinos. Together with the measurements of solar neutrino–electron scattering by the same detectors and the electron recoil results from LUX-ZEPLIN, these CEvNS data complement existing measurements using reactor and accelerator neutrinos. In this talk, I will highlight the potential of xenon-based dark matter detectors by presenting an analysis of their recent solar neutrino data. I will focus on the implications for both Standard Model and beyond-the-Standard-Model physics, with particular attention to flavor-dependent scenarios involving the tau flavor. This analysis yields new determinations of the weak mixing angle and improved limits on neutrino electromagnetic properties such as charge radius, electric millicharge and magnetic moment, as well as updated constraints on nonstandard neutrino interactions and the existence of a hypothetical $L_μ-L_τ$ light vector boson mediator. In the future, the improved precision expected from next-generation dark matter experiments will be crucial for refining these results and probing new physics with even greater sensitivity.

Speaker: Michela Sestu (Istituto Nazionale di Fisica Nucleare - Sezione di Cagliari)

IDM - Michela Sestu.pdf

123 The scalar coupling of the nucleon for direct detection of Dark Matter

The scalar coupling of the nucleon is a crucial quantity in theoretical studies of direct detection of dark matter. The expected event rates in these analyses are very sensitive to these hadronic matrix elements and an accurate determination is necessary in order to interpret the experimental results and constrain the different dark matter models. In this talk, I will show the current phenomenological determinations of these quantities and analyze the current discrepancy between lattice determinations and the former.

Speaker: Jose Manuel Alarcón (Universidad de Alcalá)

Alarcon.pdf

124 Dark matter freeze-in at stronger coupling: observational prospects

I review the concept of dark matter freeze-in at stronger coupling. It assumes that the Standard Model (SM) bath temperature has never been high, which allows for a significant coupling between dark matter and the SM, without thermalization. As a result, this class of freeze-in models can be probed via direct DM detection and at colliders. The framework also allows for observable warm dark matter with masses far below 1 MeV.

Speaker: Oleg Lebedev (University of Helsinki)

Zaragoza2026.pdf

Conference Picture

Poster session / Wine and Cheese

Poster Survey

Public lecture

Public Lecture / Cobferencia Publica

Touristic visit to the city centre

IDMVisit.pdf

Thursday 4 June

Plenary Session

Convener: Richard Gaitskell (Brown University)

125 Review of low-mass WIMP direct detection with ionisation detectors

Speaker: Daniel Baxter (Fermi National Accelerator Laboratory)

charge_060426.pdf

126 Making the most of the neutrino fog with direct detection experiments

Speaker: David Cerdeño (IFT-UAM/CSIC)

2026-06-IDM.pdf

127 Distinctive signatures of direct dark matter detection

Speaker: Jocelyn Monroe (Oxford University)

jmonroe_IDM_2026-v2-updated.pdf

128 Paleo-detectors: an alternative approach to direct detection

Paleo-detectors provide a novel experimental technique to search for dark matter (DM), with experimental efforts now funded by the NSF in the US as well as the Moore Foundation. In lieu of the conventional approach of operating a tonne-scale real-time detector to search for DM-induced nuclear recoils, paleo-detectors take advantage of small samples of naturally occurring rocks on Earth that have been deep underground (≳5 km), accumulating nuclear damage tracks from recoiling nuclei for O(1) Gyr. Modern microscopy techniques promise the capability to read out nuclear damage tracks with nanometer resolution in macroscopic samples. Thanks to their O(1) Gyr integration times, paleo-detectors could constitute nuclear recoil detectors with keV recoil energy thresholds and 100 kilotonne-yr exposures. This combination would allow paleo-detectors to probe DM-nucleon cross sections orders of magnitude below existing upper limits from conventional direct detection experiments.

Speaker: Dionysios Theodosopoulos (The University of Texas at Austin)

IDM2026_Dionysios_Theodosopoulos.pdf

Coffee Break

Parallel Session - Instrumentation for DM searches

Convener: Daniel Baxter (Fermi National Accelerator Laboratory)

129 Infrared scintillation light in xenon

Thanks to its excellent properties, xenon is widely used as a target material in dark matter and rare-event search experiments. Ultraviolet scintillation has long been recognized as the primary signal channel in xenon-based detectors and its properties have been well studied.
However, xenon also emits infrared light, a component which has received very little attention so far. Taking advantage of this additional signal could enhance the performance of future xenon detectors. This contribution will present recent progress in characterising the infrared scintillation of xenon in gaseous and liquid states, which appears particularly promising, including the study of its pulse-shape characteristics.

Speaker: Teresa Marrodan Undagoitia (Max-Planck-Institut für Kernphysik)

Marrodan_Infrared_IDM2026.pdf

130 Measurement of scintillation from proportional electron multiplication in liquid xenon

While many current world-leading experiments utilise dual-phase noble element time projection chambers (TPC) to perform direct dark matter searches, a potential alternative that may be simpler and easier to scale-up is a single-phase TPC. However, achieving similar background discrimination and event localisation capabilities as current experiments is made challenging due to the requirement of proportional scintillation and charge amplification directly in the liquid. Methods to achieve such amplification have been demonstrated using thin wires and micro pattern detector structures, but how they might be incorporated into an experiment remains elusive. We present a new approach to this, with the first results with a novel method for charge amplification in liquid xenon that could be scaled to the size required for a direct dark matter search experiment. A thin needle-like electrode was used to provide a sufficiently high electric field in a liquid xenon time projection chamber test bench, read-out by two PMTs. The experimental set-up will be presented, along with measurements of the proportional scintillation in the liquid phase at several voltages. Progress towards a scalable design, where the electrodes are incorporated into a multi-anode structure, like that employed by the spherical proportional counter used by NEWS-G, will be discussed, as will how this could be implemented in a single-phase xenon detector like XMASS-I.

Speaker: Patrick Knights (University of Birmingham)

knights_idm_2026.pdf

131 Ultra-cold Argon-based Time Projection Chamber demonstrator with wavelength-shifting capable optical amplification structures

In this work we report the initial results of the first ultra-cold argon gas Time Projection Chamber (Ar-TPC) demonstrator developed at Astrocent, instrumenting both primary (S1) and secondary (S2) scintillation signals using a single optical readout plane, blind to Ar scintillation. This milestone represents a significant step forward in the development of compact, high-performance Ar-TPC technology for direct dark matter searches.

The novelty of this work lies in the use of wavelength-shifting optical amplification structures, wavelength-shifting FAT-GEMs (field assisted transparent gaseous-electroluminescence multipliers), instead of the standard and widely-used meshes in ultra-cold Ar gas (about -180 C). By integrating a wavelength shifter directly into these optical amplification structures it is possible to convert the vacuum ultraviolet (VUV) scintillation produced by argon (peaked at 128 nm) into the visible region, enabling efficient detection by standard blue-sensitive silicon photomultipliers (SiPMs). This dual functionality, simultaneous optical amplification and wavelength shifting, allows to improve the signal collection efficiency, with this structures allowing already to reach scintillation yields similar to the ones originated in meshes.

For this initial characterization of the setup, an alpha-particle source was used. Results demonstrate the wavelength-shifting FAT-GEM's capability to efficiently convert and collect scintillation signals originated in ultra-cold Ar in a single readout plane. This solution, apart from simplifying the optical readout, enables the development of back-to-back TPC solutions. In addition to the detailed description of the proof-of-concept demonstrator, we will present the initial results of the characterization of these novel optical amplification structures highlighting its potential for dark matter searches.

The results presented serve as a stepping stone for a wider research programme aiming at demonstrating the FAT-GEM technology as a promising and scalable solution for dual-phase liquid TPCs, aiming at tonne-scale.

Speaker: Dr Pedro Costa e Silva (Astrocent / CAMK PAN)

IDM026_pedroSilva_june2026.pdf

132 Time resolution for direct dark matter detection

The impact of time resolution on achievable sensitivity across different generation rates has been investigated for direct light dark matter searches using deep sub-electron noise silicon detectors. In relevant experiments --- most prevalent using Skipper CCD or RNDR-DEPFETs --- the effective exclusion parameter space is predominantly limited by mass, exposure and background. A faster readout reduces the probability of multi-electron background per readout cycle events, caused by pile-up of thermal generated single electron events, enabling a distinguishable separation between background events and expected dark matter signals for two or more electron events.

To quantify the correlation between time resolution and sensitivity, a modular python-based simulation framework was built, utilizing the DarkELF package to simulate dark matter--electron scattering, assuming idealized Poisson--Gaussian background modulation and detector specific timing and pixel architecture. This enables a trade-off study between time resolution and detector mass across different generation rates and evaluates whether improved time resolution can compensate for increased background or reduce the necessary exposure.

The studies are motivated by the DANAE experiment, which employs RNDR-DEPFET active pixel sensors with repetitive non-destructive readout for direct dark matter searches. Compared to Skipper CCDs, RNDR-DEPFETs exhibit larger pixels and therefore higher generation rates. Skipper CCD experiments achieve very low background levels but sequential operation results in comparatively long readout times. In contrast, DEPFET detectors can be parallelized and provide significantly shorter readout times. The presented analysis will quantitatively characterize sensitivity by comparing the size of achievable excluded parameter space for different pixel sizes, generation rates and masses. It will quantify the impact of time resolution depending on the generation rate per pixel --- and thus on pixel size. An approximate time resolution below $16\,\mathrm{s/readout}$ yields substantial improvements in exclusion reach for generation rates above $3 \times 10^{-3}\, e^{-}/\mathrm{readout/pixel}$.

Speaker: Hannah Danhel (ÖAW)

Time_Resolution_Danhel_IDM2026.pdf

133 Low-Cost Amplification and Readout Device for Directional Dark Matter Searches

Directional Dark Matter (DM) detection using low pressure gaseous Time Projection Chambers (TPCs) is regarded as a promising approach for confidently probing parameter space below the neutrino fog. The use of Negative Ion Drift (NID) gases in these detectors, such as SF₆, substantially suppress charge diffusion during the drift phase to aid particle track reconstruction. However, achieving sufficiently high gas gain in NID mixtures remains a long standing challenge due to the difficulty of initiating charge avalanches. Recent results from a novel two-stage Multi-Mesh Thick Gaseous Electron Multiplier (MMThGEM) have demonstrated that, through careful design and optimisation, gas gains approaching 10⁵ are achievable in NID gases; representing an order of magnitude improvement over previous expectations. These advances motivate renewed investigation into micromesh MicroPattern Gaseous Detector (MPGD) structures for charge amplification. Conventional fabrication techniques for MPGDs, such as ThGEMs and Micromegas, are often costly and require specialised expertise. In contrast, additive manufacturing techniques, like 3D printing, offer a cheap and rapid alternative for detector prototyping. In this talk, we present a new MPGD platform for rapid research and development, the Low-cost Amplification and Readout Device (LARD). First light measurements in low pressure CF₄ are discussed, and the future potential of this modular and scalable technology is outlined.

Speaker: Alasdair McLean (Adelaide University)

IDM2026_McLean .pdf

134 An efficient method of tuning plasma haloscopes with spirals and concentric rings

Axions provide an elegant solution to the strong CP problem and serve as a strong dark matter candidate. Recent cosmological simulations of post-inflationary scenarios indicate a preference for dark matter axions in the high-mass region above 10 GHz. To effectively probe this regime, plasma haloscopes utilize a tunable periodic metal wire array, a methodology driving the international ALPHA collaboration's upcoming searches.
Implementing a spiral packing method creates a quasi-crystalline structure that efficiently fills a cylindrical cavity. However, tuning such a complex geometry poses an engineering challenge. In this presentation, we introduce a novel resonator design tailored for the ALPHA experiment that tunes a spiral-packed wire array through a single, streamlined rotational motion. By dividing the wires on concentric rings, this mechanism achieves a tuning range of a few tens of percent while successfully maintaining the cavity's quality factor and preventing significant degradation of the form factor. We will discuss the conceptual design of this resonator and evaluate its effectiveness in optimizing the experiment's sensitivity.

Speaker: Jianyang Qi (Stockholm University)

IDM2026_Jianyang_Rinnegan.pdf

135 Searches for millicharged particles at accelerator facilities with skipper-CCD detectors

A promising approach to explore dark sectors, complementary to traditional accelerator-based searches, is the search for feebly interacting particles produced in high-energy interactions at accelerator facilities. Millicharged particles (mCPs), hypothetical particles carrying a small fractional electric charge, provide a well-motivated benchmark for such searches. Arising naturally in extensions of the Standard Model with hidden sectors and additional gauge symmetries, mCPs could be produced at accelerator facilities through several mechanisms in potentially observable numbers.

Skipper-CCD detectors, capable of measuring ionization signals with single-electron resolution and extremely low energy thresholds, enable sensitivity to the tiny energy deposits expected from these particles. Recent results from the SENSEI collaboration, as well as from the CONNIE and Atucha-II collaborations, searching for mCPs produced in the NuMI beamline and nuclear reactors, respectively, have demonstrated world-leading sensitivity to such particles.

In this talk I will present ongoing efforts to search for accelerator-produced mCPs using skipper-CCD detectors. First, I will discuss the progress of the Dark BeaTS experiment, currently being commissioned along the NuMI beamline at Fermilab and building on recent hardware developments for large skipper-CCD detectors. I will then present the first results from the first year of operations of MOSKITA, a skipper-CCD detector installed near the CMS interaction point at CERN, which collected integrated luminosities of 113.3 fb⁻¹ and 1.54 nb⁻¹ during the 2024 proton–proton and Pb–Pb collision periods, respectively. Together, these efforts provide valuable input for future accelerator-based dark sector searches using low-threshold silicon detectors.

Speaker: Brenda Cervantes (Fermilab)

BrendaCervantes_IDM2026.pdf

Parallel Session - Light Dark Matter

Convener: Laura Molina Bueno (IFIC (CSIC/UV))

136 The SHiP/NA67 experiment at the ECN3 high-intensity beam facility at the CERN SPS

The SHiP/NA67 experiment is a general-purpose intensity-frontier experiment for the search for feebly interacting and long-lived GeV-scale particles and to perform neutrino physics measurements at the HI-ECN3 (high-intensity) beam facility at the CERN SPS, operated in beam-dump mode, taking full advantage of the available $4\times 10^{19}$ protons per year at 400 GeV. The Collaboration is now in the TDR preparation phase.
The setup consists of two complementary detector systems downstream of an active muon shield: the scattering and neutrino detector (SND), which includes a light dark matter (LDM) neutrino target with vertexing capability. and the hidden sector decay spectrometer (HSDS), consisting of a 50 m long decay volume followed by a spectrometer, timing detector, and a PID system. BDF/SHiP offers unprecedented sensitivity to the decay and scattering signatures of various new-physics models, including sterile neutrinos and dark sector particles.

Speaker: Richard Jacobsson (CERN)

2026_06_04_IDM26_SHiP_Jacobsson.pdf

137 New Dark Sector Results from he FASER Experiment at the LHC

The FASER experiment at the LHC is designed to search for light, weakly-coupled new particles as probes of dark sector physics. The experiment has been running since 2022, and has collected nearly 200/fb of pp collision data. FASER has new results from a search for long-lived dark photons and long-lived axion-like-particles (also interpreted in several other scenarios). This talk will present our latest results, summarize the long-lived BSM particle search program and discuss future prospects.

Speaker: Ansh Desai (University of Oregon)

2026_FASER_IDM.pdf

138 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 center-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. We present new searches in a $600~\mathrm{fb}^{-1}$ sample collected by Belle II, including searches for a light dark photon decaying to a pair of muons, an axion-like particle decaying to two photons, and a $Z^{\prime}$ boson that decays invisibly. Using a $711~\mathrm{fb}^{-1}$ 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: Youngjoon Kwon (Yonsei University)

IDM2026_Belle_II_Y.Kwon_v.1.1.pdf

139 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. 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: Craig Group (University of Virginia)

IDM2026_LDMX.pdf

140 The Impact of Cavities on Quadratically Coupled Ultralight Dark Matter

Ultra-light scalar fields may explain the nature of the dark matter in our universe. If such scalars couple quadratically to particles of the Standard Model the scalar acquires an effective mass which depends on the local matter energy density. The changing mass causes the field to deviate from its cosmological value in experimental environments. We show that the presence of a local over-density enclosing the experiment, for example a cavity, vacuum chamber, or laboratory can strongly suppress the value of the scalar and its gradient in the interior. This makes detection of such scalar dark matter challenging, and significantly relaxes constraints on strongly coupled models. However, we find that constraints derived from the motion of satellites, which lack an enclosing matter environment, are expected to withstand this effect. We demonstrate this, using bounds on the anomalous pericentre precession of the LAGEOS II satellite to generate new constraints.

Speaker: Angus Macdonald (University of Nottingham)

AngusMacdonaldIDM.pdf

141 From Smooth to Stochastic: Galactic Supernova Fluxes of MeV Dark Matter and ALPs

Core-collapse supernovae can produce light, weakly interacting particles with MeV-scale masses, such as light dark matter or axion-like particles. After escaping the supernova core with semi-relativistic velocities, these particles propagate through the Galaxy and may reach Earth long after the explosion. Since they propagate with a spread in velocities, the particles from a single supernova arrive as a highly extended packet that can span thousands of years.

It is often assumed that the superposition of packets from many past Galactic supernovae results in a smooth and stationary diffuse flux that can be searched for in terrestrial detectors. In this work, we revisit this approximation and analyze it critically, emphasizing two ingredients that are typically neglected: the finite observation time of detectors and the energy-dependent time structure of the particle packet emitted by each supernova. Considering realistic experimental timescales, detectors effectively probe only a narrow energy slice of each packet, rather than the full spectrum.

Motivated by these effects, we develop a stochastic description of the diffuse flux by simulating the supernova history of our galaxy and computing the resulting distribution of detectable signals. We show that they exhibit sizeable fluctuations in the spectral shape, reflecting the stochastic nature of the SN population. In contrast, the commonly used diffuse approximation effectively averages over these fluctuations and tends to systematically overestimate the expected flux in detectors. Our framework provides a more realistic prediction of the signal and its variability, and naturally allows us to explore the low-mass regime in a consistent way. As an application, we revisit constraints on MeV-scale fermionic dark matter and axion-like particles, obtaining revised bounds based on this stochastic treatment.

This talk is based on https://arxiv.org/pdf/2602.17597

Speaker: David Alonso-González (IFT (UAM-CSIC))

AlonsoGonzalez_IDM2026.pdf

Parallel Session - Cosmology II

Convener: Jacobo Asorey Barreiro (CAPA & Universidad de Zaragoza)

142 Non-Cold dark matter from Burdened Black Holes

Non-cold dark-matter particles can arise from the evaporation of primordial black holes (PBHs). In this talk, I'll discuss how memory-burden effect, that delays the full evaporation of black holes, affects the Lyman-α bound on such non-cold dark-matter particles. In the latter framework, PBH evaporation generically leads to two distinct dark-
matter populations with different velocity dispersions, which can imprint observable signatures on the matter power spectrum and impact small-scale overdensities. This is used to reinterpret Lyman-α forest constraints for thermal warm dark matter. In particular, I'll show that even subdominant non-cold dark-matter particle components from PBH evaporation can be constrained and confirm that non-cold dark-matter can only account for all the dark matter in the absence of PBH domination, as in the semi-classical case.

Speaker: Laura Lopez Honorez

26-IDM-LLH.pdf

143 The signature of major mergers on the hydrostatic mass bias of galaxy clusters

Galaxy clusters are powerful cosmological probes and play a central role in constraining the properties of dark matter through their mass function and abundance evolution. However, cluster mass estimates derived from intra-cluster medium observations typically assume hydrostatic equilibrium, introducing a systematic bias that propagates into cosmological and dark matter constraints. This bias is expected to be particularly significant during strong assembly phases, such as major mergers, potentially affecting precision measurements relevant to dark matter studies.

In this work, we investigate how cluster mergers impact the evolution of the hydrostatic mass bias across cosmic time and assess the physical mechanisms driving its variability. We analyse a sample of cluster mergers identified in cosmological simulations spanning the redshift range
1.5>z>0. True masses are compared with hydrostatic estimates computed within the virial volume from gas density and temperature profiles, and their evolution is connected to merger histories derived from halo merger trees.

We find that the bias exhibits a characteristic time-dependent pattern during major mergers: a pronounced negative dip around the merger time, followed by a transient positive peak and a gradual relaxation to pre-merger levels. This evolution is primarily driven by morphological reconfigurations of the intra-cluster gas density rather than thermodynamic effects. The trend shows little dependence on secondary merger parameters and can be described by a simple time-dependent functional form. Similar behaviour is observed at smaller radii, with reduced amplitude and shorter timescales.

Our results demonstrate that the hydrostatic mass bias is tightly linked to cluster assembly history, with direct implications for cluster-based cosmological analyses. Accurately modelling this time-dependent bias is essential to reduce systematic uncertainties in cluster mass calibration and to improve the robustness of dark matter constraints derived from cluster surveys.

Speaker: Isac Barranco Llorca (Departament d'Astronomia i Astrofísica, Universitat de València)

Merger signature in GC mass (Isac Barranco Llorca).pdf

144 New insights on low-mass dark matter subhalo tidal tracks via numerical simulations

A number of studies assert that dark matter (DM) subhaloes without a baryonic counterpart and with an inner cusp always survive no matter the strength of the tidal force they undergo.
In this work, we perform a suite of numerical simulations specifically designed to analyse the evolution of the circular velocity peaks ($V_\mathrm{max}$, and its radial value $r_\mathrm{max}$) of low-mass DM subhaloes due to tidal stripping. To perform this task, we have employed the improved version of the DASH library, introduced in our previous work Aguirre-Santaella et al. (2023) to study subhalo survival.
We follow the tidal evolution of a single DM subhalo orbiting a Milky Way (MW)-size halo with a baryonic disc and a bulge replicating the actual mass distribution of the MW and evolving with time. We simulate subhaloes with unprecedented accuracy, varying their initial mass, concentration, orbital parameters and inner slope (NFW and prompt cusps are considered).
Here, we also broaden our vision with respect to previous literature not just characterizing tidal tracks at the apocentres, but exploring the pericentres as well, and we find some discrepancies.
For our fiducial setting, we find $V_\mathrm{max}$ to change approximately the same after each orbital period, whilst $r_\mathrm{max}$ decreases less drastically for later orbits. This implies a larger increase in velocity concentrations for the first orbit compared to subsequent ones.
In general, $r_\mathrm{max}$ shrinks more than $V_\mathrm{max}$, leading to a continuous rise of subhalo concentration with time. The velocity concentration at present is found to be up to two orders of magnitude higher than the one at infall.
These findings significantly enhance our understanding of the dynamics and properties of low-mass DM subhaloes, providing valuable insights for future research, simulations and observations, as well as for indirect searches of DM.

Speaker: Dr Alejandra Aguirre-Santaella (Universitat de València)

AAguirreSantaella-ttracks-IDMz26pdf.pdf

AAguirreSantaella-ttracks-IDMz26.pptx

145 Axion streams are not bound to stay

We study the tidal disruption of axion miniclusters (AMCs) due to gravitational interactions with stars in the Milky Way. Axion miniclusters are compact objects composed of QCD axions, formed around matter–radiation equality, with masses in the range $10^{-16}$-$10^{-10}\,M_\odot$. Stellar encounters can tidally disrupt these structures, potentially generating streams of axions.

Using Monte Carlo simulations of AMC–star encounters, we show that the resulting tidal streams are not gravitationally bound and gradually dissolve into the Galactic halo. We estimate the dissolution timescale as a function of impact parameter, AMC mass, and stellar mass. Based on these lifetimes, we assess the implications for direct axion detection, in particular for haloscope experiments.

Speaker: Momchil Naydenov (Sofia University "St. Kliment Ohridski")

AMCs_Zaragoza.pdf

146 Novel constraints on the primordial power spectrum from compact objects formation

The primordial power spectrum of matter density perturbations contains highly valuable information about new fundamental physics, in particular cosmological inflation, but is only very weakly constrained observationally for small cosmological scales k ≳ 3 Mpc^−1. In this talk, I will show how the formation of ultracompact minihalos in the early universe can help place significant constraints over a large range of such scales. I will begin with an overview of the formation and evolution of UCMHs, then present an updated compilation of observational bounds derived from various sources. Finally, I will discuss how constraints on the abundance of such objects can be translated into upper limits on the amplitude of primordial curvature perturbations

Speaker: Sergio Sevillano Muñoz (University of Pennsylvania)

Sergio_Sevillano_IDM_UCMH.pdf

147 Dark matter and gravitational wave signals from a phase transition in the early universe

A strong first-order phase transition offers the intriguing possibility of explaining the stochastic gravitational wave background at nHz frequencies. In order to avoid cosmological constraints, such a phase transition must have occurred in a dark sector with non-negligible couplings to the standard model - opening promising avenues of
connecting the gravitational wave signal to the cosmological dark matter abundance. In order to illustrate this, I will consider a classically conformal dark sector with a U(1) gauge symmetry. The spontaneous breaking of this symmetry generates both gravitational waves and sources the mass of a fermionic sub-GeV dark matter candidate. Contact with the standard model is established through kinetic mixing of the U(1) gauge bosons with ordinary photons, a possibility that is actively being searched for at various collider experiments. I will discuss the rich phenomenology of such a scenario, demonstrating that it can successfully generate both the observed nHz gravitational wave background and the cosmological dark matter abundance, while at the same time avoiding all current constraints.

Speaker: Torsten Bringmann (University of Oslo)

Bringmann_IDM.pdf

13:30 Lunch

Parallel Session - Instrumentation for DM searches

Convener: Silvia Scorza (LPSC - CNRS)

148 Radiopurity and Cleanliness Control in next generation dark matter direct detection experiment, XLZD

In this talk I will outline the unique challenges of scaling up, and efforts we are exploring to push down background of the next-generation xenon dark matter direct-detection experiment, XLZD. The detector is envisioned as a 60-80 tonne active liquid xenon time projection chamber and rare event observatory, building upon the expertise of the XENON, LZ, and DARWIN collaborations with multi-science goals including dark matter detection and neutrinoless double beta decay studies. The scale‑up and expanded science reach introduce significant challenges, particularly in achieving the far stricter cleanliness and radiopurity requirements associated with such a detector. I will place particular emphasis on the radiopurity and cleanliness efforts that shape its design.

A multi‑tiered research and development programme is being pursued, including advances in high‑sensitivity background measurement and characterisation techniques, from mass spectrometry and gamma spectroscopy to radon emanation studies. In this talk, I will give an overview of these efforts, highlighting ongoing material selection studies such as cryostat investigations, developments in background measurement capabilities, and the broader strategies being pursued to meet the radiopurity and cleanliness goals of XLZD.

Speaker: Ferdos Dastgiri (University College London)

Dastgiri_IDM26_XLZD_RadiopurityCleanlinessControl.pdf

149 Performance of the Gd-loaded Water Cherenkov Neutron Veto in XENONnT

The Neutron Veto of the XENONnT experiment is a Gd-loaded water Cherenkov detector designed to tag radiogenic neutrons from detector materials, a primary source of nuclear recoil backgrounds in the WIMP search. It consists of a water volume surrounding the cryostat, enclosed by reflective ePTFE panels to enhance light collection and instrumented with 120 8-inch PMTs.
After the first science runs with demineralized water, the Neutron Veto was upgraded by loading the water with Gd at a mass concentration of 0.2%. Gd loading enhances neutron capture and yields a higher-energy capture signal, improving detection efficiency and shortening capture times.
The performance of the upgraded Neutron Veto during Science Run 2 is reported. The neutron tagging efficiency increased from about 50% to about 80% after Gd loading, leading to a reduction by about a factor of two of the radiogenic neutron-induced nuclear recoil background in the TPC. The upgraded system provides improved background rejection for current and future direct dark matter searches.

Speaker: Emanuele Angelino (University of Chicago)

angelino_neutron_veto_idm2026.pdf

150 Radiogenic Neutron Background Calculation: Uncertainties of the (α,n) Neutron Yields in Argon and New Cross-Section Measurement

The study of ($\alpha,n$) reactions is becoming increasingly important for the rare-event search community. Alpha particles originating from uranium and thorium decay chains can interact with detector materials, producing neutrons that may induce nuclear recoils in the region of interest for direct dark matter searches, thereby generating a background indistinguishable from a WIMP signal.

A reliable prediction of the resulting neutron yield requires precise knowledge of the relevant ($\alpha,n$) cross-sections. However, current calculations are affected by significant uncertainties. In particular, the ${}^{40}$Ar($\alpha,n$) cross-section has never been directly measured in the energy range relevant for WIMP searches.

In this talk, I will discuss the uncertainties associated with the calculation of neutron backgrounds in dark matter experiments, with particular emphasis on the impact of argon cross-section uncertainty on the neutron background evaluation for DarkSide-20k. Finally, I will present the work in progress towards a direct measurement of the ${}^{40}$Ar($\alpha,n$) cross-section by a newly formed Spanish collaboration.

Speaker: Julian Guerrero Canovas (CIEMAT)

IDM2026-Julian Guerrero Canovas.pdf

151 Underground environmental neutron flux measurement with the CYGNO project

A precise characterization of the environmental neutron spectrum in underground laboratories is crucial for designing future large-scale detectors and improving background modelling in rare-event searches. While fast neutrons already pose a significant background, thermal neutrons are expected to gain importance due to neutron-induced activation of detector materials. Previous flux estimates at Laboratori Nazionali del Gran Sasso (LNGS), one of the largest underground laboratories in the world, relied on indirect methods that offered limited spectral detail and produced inconsistent results. The CYGNO experiment offers a more direct approach using a high-resolution gaseous Time Projection Chamber (TPC), filled with a He:CF₄ (60:40) gas mixture and equipped with a triple-GEM amplification stage. Its dual optical readout via sCMOS cameras and PMTs enables full 3D reconstruction of particle tracks. In this context, LIME, the largest CYGNO prototype, completed two neutron data campaigns in the LNGS connection gallery, comprising both environmental monitoring and dedicated AmBe-source runs. In this contribution, we will present the preliminary results obtained with a newly structured analysis framework, developed for these campaigns. This methodology, along with CYGNO’s directionality capabilities, will allow for a more detailed and accurate underground neutron flux determination.

Speaker: Melba D'Astolfo (Gran Sasso Science Institute)

idm2026_dastolfo.pdf

152 Development and performance of the PandaX veto system

PandaX is a direct detection dark matter and neutrino experiment located at the China Jinping Underground Laboratory (CJPL). It utilizes liquid xenon technology to search for dark matter particles and study neutrino physics. Neutron- and gamma-induced backgrounds can be mitigated using an external veto detector. In this presentation, I will introduce the performance of a water Cherenkov veto detector in the current PandaX-4T stage and the development efforts for a novel cold-liquid scintillator veto technology for the next-generation liquid xenon experiment.

Speaker: Prof. Yuehuan Wei (Sun Yat-sen University)

YWei_PandaX_Veto_IDM2026.pdf

153 Characterization of argon recoils at the keV scale 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 Qy 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
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. ReD collected and characterized a sample of nuclear recoils down to 2 keV, thus meeting its design goal.

The ReD effort is being further extended by a new project, ReD+, at INFN Laboratori Nazionali del Sud. ReD+ is designed to reach a threshold of 0.5 keV by using the same conceptual design of ReD and improved components. A dedicated run using a deuterium-deuterium generator is then planned to achieve 0.2 keV.

In this contribution, we describe the experimental setup and present the final results on Qy down to 2 keV from the data analysis of ReD. We also discuss the perspectives to further lower the coverage down to the sub-keV range with ReD+.

Speaker: Maximo David Ave Pernas (Gran Sasso Science Institute)

Ave-IDM-2026.final.pdf

154 Modeling the low-energy accidental coincidence background in the LUX-ZEPLIN experiment

The LUX-ZEPLIN (LZ) experiment operates a dual-phase xenon time projection chamber with a 7-tonne active mass, which detects both scintillation photons (S1) and ionization electrons (S2) from particle interactions. LZ has recently placed world-leading limits on dark matter-nucleon scattering cross sections for masses down to 5 GeV/$c^2$ and reported 4.5𝜎 evidence of coherent elastic neutrino-nucleus scattering (CE𝜈NS) from $^8$B solar neutrinos. These results rely on robust modeling of low-energy detector backgrounds, which can mimic signal events. The dominant background in this regime arises from accidental coincidences of “isolated” S1- and S2-like pulses, which are produced by various instrumental effects. In this talk, I will describe the construction of an accidental background model that accounts for the time dependence of these effects, and present a series of validations that demonstrate excellent agreement with data down to keV-scale recoil energies.

Speaker: Ruben Coronel (Stanford University)

Coronel_IDM2026.pdf

Parallel Session - Direct Detection / Light DM

Convener: Guillaume Giroux (Queen's University)

155 Searching for light dark matter with the CRESST experiment

CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) is a direct-detection experiment that searches for dark matter through elastic scattering off nuclei in cryogenic calorimeters operated at temperatures of about 15 mK. Thanks to energy thresholds of O(10 eV), CRESST achieves sensitivity to dark matter in the sub-GeV mass range, reaching unprecedented performance in this regime.
In 2019, CRESST reported the first observation of a rising event rate at energies below 200 eV. This unknown background component, referred to as the Low Energy Excess (LEE), has emerged as a major limitation to the sensitivity of a wide range of low-threshold direct-detection experiments. Understanding and mitigating its origin are primary objectives of the ongoing CRESST data-taking campaign.
In this contribution, we provide an overview of the CRESST experiment, discuss recent observations and studies dedicated to understanding the LEE, and report on the latest dark matter search results.

Speaker: Francesca Pucci (LNGS)

Pucci_CRESST_IDM2026.pdf

156 BULLKID-DM: direct detection of light WIMP dark matter with a monolithic arrays of cryogenic detectors

BULLKID-DM is a new experiment designed to search for low-mass WIMP-like dark matter particles (1~GeV/c$^2$ or below) with nucleon cross-sections below 10$^{-41}$~cm$^2$. The detector consists of an 800~g array of over 2000 silicon dice, each acting as a particle absorber instrumented with multiplexed Kinetic Inductance Detectors (KIDs). Background rejection is achieved through a fully active structure, enabling fiducialization and anticoincidence techniques.

A 20~g prototype, consisting of 60 voxels diced from a 3'' silicon wafer, demonstrated the feasibility of this approach. Following its success, we present the first operation, in a surface laboratory equipped with a lead and copper radiation shield, of a 60~g demonstrator with 180 dice. This setup closely replicates the final experimental configuration. The recorded backgrounds are compared to Geant4 simulations performed by the collaboration.

We also discuss ongoing R\&D activities, including low-radioactivity detector mounting, a cryogenic scintillating veto readout with KIDs, in situ calibration techniques, and detector upgrades such as KIDs with dedicated phonon-collecting structures and germanium substrates for multi-target capabilities.

Finally, we outline the deployment plan of the setup at the Gran Sasso underground laboratory (LNGS). The demonstrator will be installed at LNGS, in the cryo-platform, by late 2026. Following successful validation, the full experiment is expected to be commissioned in 2027.

Speaker: Giorgio Del Castello (Istituto Nazionale di Fisica Nucleare (Italy))

BULLKID_IDM.pdf

157 The Tesseract Sub-GeV Dark Matter Experiment

The TESSERACT project will search for sub-GeV dark matter via multiple complementary advanced, ultra-sensitive phonon detectors, sensitive to nuclear-type, electron-type, and dark photon-type DM interactions, using three detector technologies: superfluid helium (HeRALD), polar crystals (GaAs and sapphire, SPICE), and germanium/silicon bolometers. Those detectors will share Transition Edge Sensors (TES) for phonon readout and experimental settings. Besides maximising sensitivity, this multi-target approach also allows us to identify and discriminate against novel instrumental and physical backgrounds. The experiment is presently in a period of targeted R&D, with the first physics results based on demonstrator setups to be expected this year and all detectors working. Full integration of the TESSERACT setup at the Modane Underground Laboratory (LSM) is planned for 2028. We will present the status of the experiments and sensors, expected sensitivities, and possible ways to achieve sub-MeV dark matter mass sensitivity.

Speaker: Daniel McKinsey (University of California, Berkeley)

TESSERACT overview IDM - McKinsey.pdf

158 Progress and Results from HVeV@CUTE

The SuperCDMS-HVeV (High-Voltage with eV resolution) program is an
R&D project focused on developing detectors with low energy resolution to search for low-mass dark matter (≲ 1 GeV/c^2), study charge-transport in cryogenically cooled crystals, and probe unclassified backgrounds at low energy. The program utilizes gram-scale silicon detectors instrumented with TES (transition-edge sensor)-based phonon sensors. A high-voltage bias can be applied to the crystal to amplify phonon signals from ionizing interactions via the Neganov-Trofimov-Luke effect. Utilizing these tools, HVeV detectors have recently achieved sub-eV baseline energy resolutions and demonstrated competitive sensitivities to electron-recoil dark matter at masses below 1 MeV/c^2. This talk will show results from a data-taking campaign conducted at the CUTE facility at SNOLAB using an HVeV detector with a sub-eV baseline resolution. Included in these results are observations of the Low Energy Excess and progress on an electron-recoil dark matter search

Speaker: Kyle Kennard (Northwestern University)

KKennard_IDM26.pdf

159 First Results from a GaAs cryogenic Calorimeter for the DAREDEVIL project

The DAREDEVIL (DARk-mattEr-DEVIces-for-Low-energy-detection) project aims to develop a new generation of detectors to search for dark matter candidates with masses below 1 GeV/c². The detection strategy relies on dark matter–electron scattering, where the excitation energy of electrons must match the momentum transferred in the interaction. Therefore, materials with very small energy gaps (of the order of eV or below) are particularly suitable. Promising candidates include special semiconductors, Dirac semimetals, Weyl semimetals, and scintillating materials, which have been extensively studied theoretically and are now being explored experimentally within the DAREDEVIL project.

The first phase of the project focuses on the development of gram-scale detectors with energy thresholds in the meV range, optimized for the detection of light dark matter via electron scattering. To achieve the sensitivity required to detect such small energy depositions, the selected crystals are used as absorbers in low-temperature calorimeters with dual phonon and infrared-photon readout.

In this contribution, we present the first results obtained with a low-temperature calorimeter based on a GaAs crystal, operated at 15 mK and coupled to a Neutron Transmutation Doped (NTD) thermistor for phonon readout. In addition, we report the first tests of the dual-readout technique, performed with a germanium light detector exploiting the Neganov–Trofimov–Luke (NTL) effect to amplify the phonon signal.

Speaker: Dounia Helis (INFN-LNGS)

Slides_IDM_2026_Dounia_Helis.pdf

Parallel Session - Theory/Phenomenology

Convener: Sven Heinemeyer (IFT (CSIC, Madrid))

160 Picolensing as a probe of massive compact dark objects

Compact supermassive dark-matter (DM) states act as gravitational lenses. Widely spatially separated space-based gamma-ray detectors would observe geometrical parallax of such an intervening lens with respect to cosmologically distant gamma-ray bursts (GRB). This parallax can be of order the Einstein angle of the lens, resulting in a significant differential magnification of the source as viewed from the two detectors. Simultaneous brightness measurements of the same GRB made by two detectors can therefore detect or exclude such DM states. Recent studies have shown that this "picolensing" signal could be a promising way to search in particular for primordial black hole (PBH) dark matter in part of the "asteroid mass window", roughly $10^{-15} < M_{\text{PBH}}/ M_{\odot} < 10^{-10}$. In this talk, I will discuss my work to explore the robustness of this signal to various uncertainties not previously carefully accounted for: most importantly, to uncertainties in the transverse extent of the observed GRB emission region. I'll show that, while large GRB source-size uncertainties do degrade previous projections somewhat, it is still possible to probe most of the PBH DM asteroid mass window with a future mission that employs two Swift/BAT-class detectors separated by a distance on the order of an AU. Depending on the total number of GRBs that such a mission ultimately observes, it may even be possible to robustly probe new subcomponent DM parameter space at PBH masses above the window, potentially as high as $2 \times 10^{-8} M_{\odot}$. Time permitting, I will also discuss recent work to extend this observable to the detection of spatially extended dark lenses, such as QCD axion miniclusters.

Speaker: Michael A. Fedderke (Perimeter Institute for Theoretical Physics)

Fedderke_IDM2026-v2.pdf

161 Charting the dark matter landscape with matter-wave interferometers

In this talk, I will present two novel theoretical ideas to search for dark matter (DM) across qualitatively distinct regions of model space with a genuine quantum sensing technique: matter-wave interferometry. I will begin by presenting new theoretical work establishing the in-in (Schwinger-Keldysh) formalism as the natural language for matter-wave interferometry, e.g., demonstrating how it elucidates coherent enhancements and the conditions under which they arise. I will then show how a trapped-ion interferometer, originally conceived for rotation sensing, would be sensitive to Rutherford scattering of sub-GeV millicharged particle DM with large effective electric charge off a heavy ion via collisional decoherence. Since these detectors are effectively threshold-free, trapped-ion interferometers are poised to outperform existing ion-trap and other direct detection experiments across a substantial region of parameter space. I will further show that tabletop experiments designed to test the quantum nature of gravity via gravity-induced entanglement between two massive wavepackets are naturally sensitive to quadratically-coupled scalar DM. Indeed, DM coupling to nucleons generates a position-dependent in-medium potential proportional to the DM occupation number which, at the wave-particle boundary (i.e., for DM masses ~ 10 eV), would entangle two otherwise uncorrelated masses, thus constituting a qualitatively new observable.

Speaker: Leonardo Badurina (Caltech)

IDM2026-2.pdf

162 Beyond standard dark matter phenomenology in terrestrial and space-based quantum sensors

The development of high-precision quantum sensors is an exciting prospect for all branches of science and metrology. Chief among these are their applications in astroparticle phenomenology from detection of gravitational waves to illuminating the nature of dark matter. Studies naturally concentrate on the simplest models of new physics phenomena - scalar fields with linear couplings in the Standard Halo Model. However, it is essential to consider the broadest landscape of parameter space in reach.

Atom interferometers, atomic clocks, and other quantum sensors can constrain models of Lorentz invariant and Lorentz violating spin-2 dark matter, motivated by theories of massive gravity. We show that coherent oscillations of the spin-2 ultra-light field induces measurable phase shifts in atoms through three coupling mechanisms; scalar interactions that modify atomic energy levels, and vector and tensor effects that alter the propagation of both atoms and light. We demonstrate that these multifaceted interactions enable experiments to probe a range of ULDM properties and mass scales that are inaccessible to laser interferometric gravitational wave detector.

In addition to terrestrial experiments, I also discuss future modalities for space-based quantum sensor missions. Assaying the distribution of dark matter in the solar system is determined by the gravitational focusing of the Sun and planets and the effects of self-interactions, that can yield bound populations of dark matter at sub-Solar-system scales. Notably, the wave dark-matter candidates in the axiverse of string theory support a great variety of particle masses, and the possibility of structured, time varying over-densities from overlapping planetary halos in the Solar system offers a striking way of identifying multiple-dark-matter-particle scenarios.

Work based on arXiv:2412.14282 and a future publication. In collaboration with Diego Blas, Christopher McCabe, and Susan Gardner.

Speaker: John Carlton (DESY)

IDM2026_JCarlton.pdf

163 Direct Detection of CP Violation in Baryonic Dark Matter

We consider a QCD-like theory with two light flavours, in which the DM candidate is a dark neutron. In this scenario, a non-vanishing theta angle triggers velocity-dependent self-interactions with dark pions acting as light mediators. By further considering a dark photon portal to the SM, direct-detection experiments probe CP violation via magnetic- and electric- dipole-mediated scatterings induced by the theta angle. We further discuss indirect detection signatures from DM annihilation, which are p-wave or loop suppressed, as well as thermalization in the early Universe and the resulting relic abundance.

Speaker: Pablo Figueroa (Instituto de Física Corpuscular, UV-CSIC)

IDM_2026_Pablo_Figueroa.pdf

Coffee Break

Conference Dinner

cenaIDM2026.pdf

Friday 5 June

Plenary Session

Convener: Karl van Bibber (University of California Berkeley)

164 Illuminating the Dark: Review on the dark matter searches at the LHC

This talk reviews and summarizes the latest dark matter searches at the LHC conducted by the ATLAS and CMS collaborations, covering a broad range of experimental signatures, including conventional missing transverse momentum topologies to more exotic regimes, such as long-lived particles and dark sector phenomena. Both classic WIMP and alternative non-WIMP scenarios will be covered.

Speaker: Zirui Wang (Fudan University (CN))

wangzr20260605_IDM_DM.pdf

165 Light Dark Matter searches at fixed-target experiments

The origin and composition of Dark Matter (DM) remain one of the major open questions in particle physics. Dark Sectors (DS) provide a compelling framework in which DM can arise as a thermal relic in the sub-GeV mass range (the so called Light DM). In this talk, I will provide an overview of the potential of fixed target experiments to probe such scenarios and of their complementarity with collider and direct detection searches.
In particular, I will focus on NA64, one of the world leading experiments searching for DS. The experiment pioneered the active-dump technique and exploits uniquely the use of complementary high-energy beams available at the CERN Super Proton Synchrotron accelerator: e-/+, muon, and hadron beams. Its physics program targets LDM models and a variety of New Physics scenarios below the electroweak scale (ALPs, inelastic DM, Lepton Flavour Violation, Z’ in B-L and Lμ-L𝜏 models…). I will present the latest results obtained by the experiment as well as the expected projections from the analysis of the statistics collected until 2026. Finally, I will discuss the future prospects of the experiment beyond the next CERN shutdown.

Speaker: Laura Molina Bueno (IFIC (CSIC/UV))

molina_iDM2026_5062026.pdf

166 Charting the Dark Sector: Theoretical Perspectives on Dark Matter

Speaker: Nicolao Fornengo (University of Torino and INFN/Torino)

Fornengo_IDM2026.pdf

167 IDM 2026: experimental overview

This talk will summarize the main topics and results discussed during the week of the conference, focussing on direct dark matter detection, axion searches, and detector instrumentation.

Speaker: Teresa Marrodan Undagoitia (Max-Planck-Institut für Kernphysik)

Marrodan_IDM_summary.pdf

168 Concluding Remarks

Speaker: Igor García Irastorza (Centro de Astropartículas y Física de Altas Energías (CAPA) - Universidad de Zaragoza)

Coffee Break: - Brunch

Visit to the Canfranc Underground Laboratory

CanfrancVisit.pdf