16th Patras Workshop on Axions, WIMPs and WISPs

Online Workshop

Online Workshop

Giovanni Cantatore (TS), Konstantin Zioutas (University of Patras , PATRAS GREECE)

The Covid-19 pandemic is unfortunately not yet under control, and health and safety concerns are still paramount in the foreseeable future. For this reason, the  International and Local Organizing Committees have decided to


Please mark these dates in your agenda.  

The nature and composition of Dark Matter and Dark Energy are two of the most pressing mysteries of frontier physics, and research in these fields is presently gathering increasing momentum and attracting the efforts of scientists from many international institutions. The "16th Patras Workshop on Axions WIMPs and WISPs” is the latest event in an annual series of conferences, started in 2005 at CERN. This workshop is aiming to continue the rich and successful series, reviewing recent theoretical advances, laboratory experiments, novel ideas as well as astrophysical and cosmological results in the fields of axions, WIMPs and WISPs. Participation by young scientists is strongly encouraged.


Hosted by: INFN, Division of Trieste; Physics Department of the University of Trieste; University of Rijeka.


Sponsored by:

  CERN       DESY       IBS/CAPP       INFN       University of Freiburg                     University of Heidelberg    University of Patras       University of Zurich     


Secretariat: Anna Paola Cuccarollo (INFN TS), Antonella Cappelletti (Trieste Traduzioni e Congressi)   

Web content manager: Anna Paola Cuccarollo (INFN TS), Nadia D'Antoni (DFis UniTS)

  • Abaz Kryemadhi
  • Adam Brown
  • Adrián Ayala-Gómez
  • Akira Miyazaki
  • Aleksandr Chatrchyan
  • Alessandro Mirizzi
  • Alessio Rettaroli
  • Alexander Derbin
  • Alexander Hipp
  • Alexander Panin
  • Alexander Sushkov
  • Amy Cottle
  • Andreas Abeln
  • Andreas Mastronikolis
  • Andreas Ringwald
  • Andrew Geraci
  • Andrew Kunwoo Yi
  • Andrew Sonnenschein
  • Andrey Pankratov
  • André Filipe Cortez
  • Anish Ghoshal
  • Ankur Agrawal
  • Anna Paola Cuccarollo
  • Anton Sokolov
  • Antonello Ortolan
  • Antonios Gardikiotis
  • Aoife Bharucha
  • Argyris Nicolaidis
  • Ariel Arza
  • Ariel Zhiitnitsky
  • Arne Wickenbrock
  • Asier Lopez-Eiguren
  • Atsushi Nishizawa
  • Axel Lindner
  • Benedikt Eggemeier
  • Benjamin Safdi
  • Bjoern Penning
  • Bodo Schwabe
  • Brian Shuve
  • Carlo Ligi
  • Caterina Braggio
  • Cem Eröncel
  • Chang Lee
  • Chelsea Bartram
  • Christoph Krieger
  • Ciaran O'Hare
  • Crystal Kim
  • Danho Ahn
  • Danial Lohrabi
  • Daniel Hengstler
  • Daniel Unger
  • Dario Soldi
  • David Leppla-Weber
  • David Marsh
  • David Tanner
  • Deniz Aybas
  • Derek Kimball
  • Dion Noordhuis
  • Diptimoy Ghosh
  • Divya Sachdeva
  • Dmitry Levkov
  • Dmitry Salnikov
  • Dominik Breitmoser
  • Dominik Utz
  • Don Niko Godilano
  • Doris Todorović
  • Eike Müller
  • Elisa Ruiz Chóliz
  • Elisa Todarello
  • Enrico Nardi
  • Erika Garutti
  • Evgeniy Unzhakov
  • Farman Ullah Sheikh
  • Federica Petricca
  • Francesco Longo
  • Francesco Schiavone
  • Frederic Lassiaille
  • Fritz Caspers
  • Gerald Eigen
  • Gioacchino Piazza
  • Giovanni Carugno
  • Giuseppe D'Auria
  • Giuseppe Lucente
  • Giuseppe Messineo
  • Giuseppe Ruoso
  • Gray Rybka
  • Guido Martinellli
  • Hanieh Karimi
  • Haowen Su
  • Hector Masia Roig
  • Hendrik Bekker
  • Henri Sieber
  • Hira Zafar
  • Horst Fischer
  • Ian Bailey
  • Igor Samsonov
  • Igor Tkachev
  • Ippei Obata
  • Jacob Egge
  • Jan Schütte-Engel
  • Jana Riess
  • Janos Adam
  • Javier Redondo
  • Jiashuo Zhang
  • Jihee Yang
  • Jinwei Wang
  • Joao Penedo
  • Joerg Jaeckel
  • Joshua Eby
  • José Matias-Lopes
  • Jun'ya Kume
  • Junu Jeong
  • Justin Baier
  • Jörn Schaffran
  • Kaan Ozbozduman
  • Keir Rogers
  • Kenichi Saikawa
  • Kensuke Homma
  • Klaus Desch
  • Klaus Eitel
  • Kohei Kamada
  • Konstantin Zioutas
  • Laura Baudis
  • Laura Manenti
  • Lennert Thormaehlen
  • Leonid Kuzmin
  • Leslie Rosenberg
  • Li-Wei Wei
  • Lingfeng Li
  • Loredana Gastaldo
  • lorenzo marafatto
  • Luca Balducci
  • Luca Di Luzio
  • Marco Gorghetto
  • Marin Karuza
  • Marios Maroudas
  • Marsh David
  • Martin Markanovic
  • Martin Spinrath
  • Martin Stahlberg
  • Martín de los Rios
  • Massimiliano Lattanzi
  • Matteo Galaverni
  • Matthew Lawson
  • Maxim Fitkevich
  • Meir Shimon
  • Michael Fedderke
  • Michael Gehring
  • Michael Hasinoff
  • Michael Perryman
  • Michael Tobar
  • Miguel Vanvlasselaer
  • Mijas Tiwari
  • Min Jiang
  • Mohamed Hassan
  • Mohammadhossein Namdar
  • Mona Dentler
  • Nuria Castello Mor
  • O. Keith Baker
  • Oindrila Ghosh
  • Pablo Quílez
  • Paola Arias
  • Paolo Gondolo
  • Paolo Spagnolo
  • Peter Matak
  • Petr Satunin
  • Philip Sørensen
  • Pierluca Carenza
  • Pierre Sikivie
  • Pranjal Trivedi
  • Raffaele Di Vora
  • Raphael Cervantes
  • Rashid Riahi
  • Reyco Henning
  • Saarik Kalia
  • Sander Vermeulen
  • Sankha Subhra Chakrabarty
  • Schumann Marc
  • Sebastian Ellis
  • Sebastian Hoof
  • Sergey Troitsky
  • Sergio Arguedas Cuendis
  • Serkant Çetin
  • Shenyang Shi
  • Shigetaka Moriyama
  • Shriram Sadashivajois
  • Sokratis Trifinopoulos
  • Sophie Mutzel
  • Soroush Shakeri
  • Stefan Knirck
  • Stefano Piacentini
  • Stephan Schiller
  • Steven Worm
  • SungWoo YOUN
  • Susana Cebrian
  • Taizhou Hong
  • Tatsumi Nitta
  • Thibaut Houdy
  • Thomas Edwards
  • Timothée Schaeffer
  • Tomas Blazek
  • Tonatiuh Matos
  • Udai Raj Singh
  • Uwe Schneekloth
  • Vaisakh Plakkot
  • Valentina Montoya
  • Valentina Muratova
  • Victor Flambaum
  • Viraf Mehta
  • William Wester
  • Wolfgang Funk
  • Xiaoyue Li
  • Xinyi Zhang
  • Yakefu Reyimuaji
  • Yannis Semertzidis
  • Yifan Chen
  • Yuka Oshima
  • Yuta Michimura
    • 1:00 PM 2:30 PM
      Session 1
      Convener: Konstantin Zioutas (University of Patras , PATRAS GREECE)
      • 1:00 PM
        Introduction 20m
        Speaker: Giovanni Cantatore (TS)
      • 1:20 PM
        Status and prospects of the ALPS II experiment 25m

        ALPS II is a light-shining-through-a-wall experiment at DESY Hamburg searching for axion-like particles aiming at a sensitivity of $g_{a \gamma \gamma} \approx 2\times 10^{-11}\,\textrm{GeV}^{-1}$ with the use of long magnet strings and resonant optical cavities. The experiment is being commissioned at present: two $120\,\textrm{m}$ long straightened superconducting dipole magnet strings have been installed and their alignment verified by shining through a properly mode-matched visible laser between the two end station cleanrooms. A thorough characterization of the optics environments in terms of vibration, seismic and thermal control for the resonant cavities is currently underway alongside the integration of the vacuum and the cryogenic systems. First science run is anticipated for late 2021/early 2022 with the coherent detection scheme where the axion-regenerated-photon is mixed with a local oscillator field. In this talk I will give an overview and status update on the ALPS II experiment, discuss the expected sensitivity of the initial science run, and the path forward to the targeted sensitivity and beyond. Progress on the complementary energy-based detection scheme with a transition edge sensor will also be reported.

        Speaker: Li-Wei Wei (Deutsches Elektronen-Synchrotron (DESY))
      • 1:45 PM
        Using Radio Observations of Neutron Stars to Probe QCD Axion Dark Matter 5m
        Speaker: Thomas Edwards (Stockholm University)
      • 1:50 PM
        Using Black Holes to Constrain the String Axiverse 5m
        Speaker: Viraf Mehta (University of Göttingen)
      • 1:55 PM
        Migdal effect and photon Bremsstrahlung: improving the sensitivity to light dark matter of liquid argon experiments 5m
        Speaker: Stefano Piacentini (Istituto Nazionale di Fisica Nucleare)
      • 2:00 PM
        Stimulated radar collider for probing gravitationally weak coupling pseudo Nambu-Goldstone bosons 5m
        Speaker: Kensuke Homma (Hiroshima University)
      • 2:05 PM
        Improvements on operation and analysis for ADMX-G2 Run 1C 5m
        Speaker: Tatsumi Nitta
      • 2:10 PM
        Ultralight vector dark matter search using KAGRA 20m

        Gravitational wave detectors are extremely sensitive to the differential arm length changes and they can be used for measuring the small displacement of the test masses due to the ultralight vector dark matter (DM). However, especially for the mirrors made of the same material, the effects of the vector DM to the different mirrors are mostly common and the sensitivity is largely attenuated. In this situation, auxiliary length channels are quite useful to extract the signature of DM by making use of the asymmetric configuration of the interferometer. We would like to emphasize that KAGRA employs sapphire test masses and fused silica auxiliary mirrors. Such a difference in materials drastically enhances the sensitivity of the auxiliary length channels and enables us to probe the unexplored parameter region of, for example, the $U(1)_{B-L}$ gauge boson. In this talk, we present the current status of the pipeline for ultralight vector DM search with KAGRA and discuss the prospects of our analysis using the data from KAGRA's first observing run in 2020.

        Speaker: Jun'ya Kume (RESCEU, Univ. of Tokyo)
    • 2:30 PM 2:50 PM
      Break 20m
    • 2:50 PM 4:20 PM
      Session 2
      Convener: Axel Lindner (DESY)
      • 2:50 PM
        True axions beyond the canonical band 35m

        In this talk, I will review the different mechanisms that have been proposed in the literature in order to solve the strong CP problem with axions that lie outside the canonical QCD axion band. The general strategy involves either enhancing/suppressing a specific Wilson coefficient among the axion couplings to SM fields, or increasing/lowering the axion mass for a given axion scale. Given the strong experimental axion program, the most relevant phenomenological consequences of such attempts will be discussed, together with possible strategies to experimentally disentangle the different possibilities.

        Speaker: PABLO QUILEZ (DESY)
      • 3:25 PM
        Dark matter annual modulation results from the ANAIS-112 experiment 25m

        An annual modulation in the interaction rate of galactic dark matter is expected by the revolution of the Earth around the Sun; a modulation signal compatible with expectations has been observed by the DAMA/LIBRA experiment for about twenty years, being one of the most puzzling experimental results in the field as it has not been confirmed by other dark matter direct detection experiments. ANAIS, using 112.5 kg of sodium iodide as target, is taking data at the Canfranc Underground Laboratory in Spain since August 2017 aiming at testing the observation by the DAMA/LIBRA experiment using the same target and technique.

        Here, the ANAIS-112 experiment will be described presenting the set-up, performance, and analysis methods and the annual modulation results from 3 years exposure will be discussed. The best fits obtained for the modulation amplitude in the [1-6] keV ([2-6] keV) energy regions are (-0.0034)±0.0042 cpd/kg/keV (0.0003±0.0037 cpd/kg/keV), supporting the absence of modulation in the data and being incompatible with the DAMA/LIBRA result at 3.3 (2.6) σ, for a sensitivity of 2.5 (2.7) σ. In addition, some complementary analyses (a phase-free annual modulation search and the exploration of the possible presence of a periodic signal at other frequencies) have been made together with several consistency checks. All the obtained results have confirmed the ANAIS-112 projection of reaching a 3σ sensitivity for the scheduled 5 years of operation.

      • 3:50 PM
        Direct detection of WIMPs of arbitrary spin 20m

        There is no compelling reason for dark matter particles to be elementary, or for their spin to be limited to 0, 1/2, or 1. Composite dark matter, for example, or mirror dark matter, or molecular dark matter with suppressed lower multipoles, may interact with nuclei through high spin operators. I will present a systematic approach to characterize the most general non-relativistic WIMP-nucleus interaction allowed by Galilean invariance for a WIMP of arbitrary spin, and a first phenomenological analysis of the direct detection of high-spin dark matter, in particular quadrupolar, octupolar, and hexadecapolar dark matter.

        Speaker: Prof. Paolo Gondolo (University of Utah)
      • 4:10 PM
        Axion Stars: Toward the Planck Scale 5m
        Speaker: Joshua Eby (Kavli IPMU)
      • 4:15 PM
        The Geomagnetic Field and the Search for Axions 5m
        Speaker: Argyris Nicolaidis (Theoretical Physics Department, Aristotle University of Thessaloniki)
    • 4:20 PM 4:40 PM
      Break 20m
    • 4:40 PM 6:00 PM
      Session 3
      Convener: DMITRY BUDKER (Helmholtz Institute Mainz)
      • 4:40 PM
        Effects of a hidden photon-dark matter background in axion-photon interactions 20m

        In this work we investigate a scenario where the dark matter of the universe is made of light hidden photons. Thanks to a $Z_{2}$ symmetry, the kinetic mixing with the photon is forbidden and the dark photon interacts with the Standard Model only via an axion-like particle, that acts as a messenger. Focusing on signatures involving the ordinary photon, our survey of the phenomenology includes limits from cosmological stability, CMB distortions, astrophysical energy loss, light-shining-through-walls experiments, helioscopes and solar X-ray observations.

        Speaker: Prof. Paola Arias Reyes
      • 5:00 PM
        COSINUS - Direct Search for Dark Matter with Cryogenic NaI Detectors 20m

        In the summer of 2021, construction of the COSINUS experiment will begin at the Laboratori Nazionali del Gran Sasso in Italy. COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches) is a direct dark matter search experiment specifically designed to cross-check the signal reported by the DAMA/LIBRA collaboration since many years. Featuring high-purity crystals of the same target material (NaI) which are operated as cryogenic phonon detectors, COSINUS also provides a two-channel readout, a trait that is unique in the landscape of NaI experiments. Through the use of an additional channel measuring the scintillation light created in particle interactions in the crystal, particle discrimination becomes possible down to energies of few keV in recoil energy. In the talk, an overview on the status of the COSINUS experiment and its detection principles will be given, as well as an outlook on the first measuring phase.

        Speaker: Martin Stahlberg (Max-Planck Institute for Physics)
      • 5:20 PM
        The DMRadio Program 20m

        DMRadio, which now includes the ABRACADABRA collaboration, is a multi-detector program to search for axion dark matter (aDM) with mass below 1 𝜇eV using a lumped-element resonator. DMRadio-50L is a toroidal detector that will probe aDM over the range 20 peV$\lt m_a\lt $ 20 neV down to photon couplings of $g_{a\gamma\gamma} > 5\times10^{-15}\,\mathrm{GeV}^{-1}$. It is currently under construction and will also serve as a testbed for acceleration with quantum sensors. DMRadio-m3, which is in the design phase, will have a larger magnet and be sensitive to aDM in the QCD axion band from 20 neV $\lt m_a \lt$ 0.8 𝜇eV. We are also pursuing the development of a future search for GUT-scale QCD axions with masses down to 1 neV, called DMRadio-GUT. In this talk I will give an overview of the DMRadio program, design considerations, and schedule. I will also present recent results from ABRACADABRA.

        Speaker: Reyco Henning (UNC Chapel Hill)
      • 5:40 PM
        Supernova bounds on axion-like particles coupled with nucleons and electrons 20m

        We investigate the potential of core-collapse supernovae (SNe) to constrain axion-like particles (ALPs) coupled to nucleons and electrons. ALPs coupled to nucleons can be efficiently produced in the SN core via nucleon-nucleon bremsstrahlung and, for a wide range of parameters, leave the SN unhindered producing a large ALP flux. For ALP masses exceeding 1 MeV, these ALPs would decay into electron-positron pairs, generating a positron flux. In the case of Galactic SNe, the annihilation of the created positrons with the galactic electron background would contribute to the 511 keV annihilation line. Using the SPI (SPectrometer on INTEGRAL) observation of this line, allows us to exclude a wide range of the axion-electron coupling, $10^{-19} < g_{ae} < 10^{-11}$, for $g_{ap}\sim 10^{-9}$. In the case of ALP decays in the extra-galactic medium, the electron-positron annihilations would yield a contribution to the cosmic X-ray background. This allows us to set constraints down to the level $g_{ae} \sim 10^{-20}$.

        Speaker: Giuseppe Lucente (Istituto Nazionale di Fisica Nucleare)
    • 6:00 PM 6:20 PM
      Break 20m
    • 6:20 PM 7:20 PM
      Session 4
      Convener: Oliver Baker (Yale University)
      • 6:20 PM
        Searches for a feebly interacting particles at the NA62 experiment 20m

        The high-intensity setup and detector performance make the NA62 experiment at CERN particularly suited for searching new physics effects from different scenarios involving feebly interacting particles in the MeV-GeV mass range.
        A search for the K+→π+X decay, where X is a long-lived feebly interacting particle, is performed through an interpretation of the K+→π+νν ̄ analysis of data collected in 2016-2018. Model- dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs. Upper limits set on the branching ratio BR(K+→π+X) improve on current limits for mX below 260 MeV/c2 and rest lifetimes above 100 ps.
        Searches for K+ → e+N, K+→μ+N and K+→μ+νX decays, where N and X are massive invisible particles, were performed by NA62 using the 2016-2018 data set.
        The N particle is assumed to be a heavy neutral lepton, and the results are expressed as upper limits of O(10−9) and O(10−8) of the neutrino mixing parameter |Ue4|2 and |Uμ4|2, improving on the earlier searches for heavy neutral lepton production and decays in the kinematically accessible mass range. The X particle is considered a scalar or vector hidden sector mediator decaying to an invisible final state, and upper limits of the decay branching fraction for X masses in the range 10-370 MeV/c2 are reported for the first time, ranging from O(10−5) to O(10−7).
        A study of a sample of 4×10ˆ9 tagged π0 mesons from K+→π+π0(γ) is performed, searching for the decay of the π0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4×10−9 is set on the branching ratio at 90% C.L. improving on previous results by a factor of 60.

        Speaker: Dario Soldi (TO)
      • 6:40 PM
        New experiment searching for solar axions with Tm-containing cryogenic bolometer 20m

        A.H. Abdelhameed$^1$, S.V. Bakhlanov$^2$, P. Bauer$^1$, A. Bento$^{1,7}$, E. Bertoldo$^1$, L. Canonica$^1$, A.V. Derbin$^2$, I.S. Drachnev$^2$, N. Ferreiro Iachellini$^1$, D. Fuchs$^1$, D. Hauff$^1$, A. Kuzmichev$^2$, M. Laubenstein$^3$, D.A. Lis$^4$, I.S. Lomskaya$^2$, M. Mancuso$^1$, V.N. Muratova$^2$, S. Nagorny$^5$, S. Nisi$^3$, F. Petricca$^1$, F. Proebst$^1$, J. Rothe$^1$, V.V. Ryabchenkov$^6$, S.E. Sarkisov$^5$, D.A. Semenov$^2$, K.A. Subbotin$^4$, M.V. Trushin$^2$, E.V. Unzhakov$^2$, E.V. Zharikov$^4$.

        $^1$ Max-Planck-Institute fur Physik, D-80805 Munchen, Germany
        $^2$ NRC Kurchatov Institute, Petersburg Nuclear Physics Institute, 188309 Gatchina, Russia
        $^3$ INFN, Laboratori Nazionali del Gran Sasso, 67010 Assergi, Italy
        $^4$ Prokhorov General Physics Inst. of the Russian Academy of Science, 119991 Moscow, Russia
        $^5$ Queen's University, Physics Department, K7L 3N6 Kingston, Canada
        $^6$ NRC Kurchatov Institute, 123182 Moscow, Russia
        $^7$ also at: Departamento de Fisica, Universidade de Coimbra, P3004 516 Coimbra, Portugal

        Intensive experimental searches for axions and axion-like particles (ALPs) are currently supported by two main circumstances: first, axions solve the strong CP problem and, second, axions are well-motivated candidates for the role of dark matter particles. Moreover, the existence of axions and ALPs could explain too rapid cooling some classes of stars and the anomalous transparency of the Universe for γ-quanta with energies of the order of 1 TeV.
        If axions do exist, then the Sun should be an intense source of these particles. Axions can be efficiently produced by Primakoff conversion of photons in the electric field of the plasma, by Compton and bremsstrahlung like and atomic processes in the hot solar plasma. The resulting axion fluxes depends on axion-photon $g_{A\gamma}$ and axion-electron $g_{Ae}$ coupling constants, respectively, and can be detected via the resonant excitation of low energy nuclear levels. The searches for the resonant absorption of solar axions by $^{169}$Tm nuclei A + $^{169}$Tm → $^{169}$Tm*(8.41 keV) → $^{169}$Tm + ($\gamma$-, e-) were proposed and carried out in [1, 2].
        In this work we used the $\rm{Tm_3Al_5O_{12}}$ crystal as cryogenic bolometer [3] to detect the X- and $\gamma$-rays, conversion and Auger electrons appearing due to de-excitation of 8.4 keV nuclear level of $^{169}$Tm. Measurements carried out with 8 g crystal for 6.6 days on the surface of the earth allowed to establish new limits on the coupling constants of the axion with photons, electrons and nucleons $g_{AN}$: $|g_{A\gamma} (g_{0AN} + g_{3AN})| \leq 1.44×10^{−14}$ GeV$^{−1}$ and $|g_{Ae} (g_{0AN}+g_{3AN})| ≤ 2.81×10^{−16}$. The obtained restrictions excluded a new range of possible values of the coupling constants $g_{A\gamma}$ and $g_{Ae}$ and axion masses $m_A$ [4].

        1. A.V. Derbin, S.V. Bakhlanov, A.I. Egorov, I.A. Mitropol’sky, V.N. Muratova, D.A. Semenov, E.V. Unzhakov, Search for solar axions produced by Primakoff conversion using resonant absorption by $^{169}$Tm nuclei, Phys. Lett. B 678 (2) (2009) 181–185
        2. A.V. Derbin, A. S. Kayunov, V.V. Muratova, D. A. Semenov, and E.V. Unzhakov, Constraints on the axion-electron coupling for solar axions produced by a Compton process and bremsstrahlung, Physical Review D 83, 023505 (2011)
        3. E. Bertoldo, A.V. Derbin, I.S. Drachnev, M. Laubenstein, D.A. Lis, M. Mancuso, V.N. Muratova, S. Nagorny, S. Nisi, F. Petricca, V.V. Ryabchenkov, S.E. Sarkisov, D.A. Semenov, K.A. Subbotin, E.V. Unzhakov, E.V. Zharikov, A test of bolometric properties of Tm-containing crystals as a perspective detector for a solar axion search, Nuclear Inst. and Methods in Physics Research, A 949 (2020) 162924
        4. A.H. Abdelhameed, S.V. Bakhlanov, P. Bauer, A. Bento, E. Bertoldo, L. Canonica, A.V. Derbin, I.S. Drachnev, N. Ferreiro Iachellini, D. Fuchs, D. Hauff, M. Laubenstein, D.A. Lis, I.S. Lomskaya, M. Mancuso, V.N. Muratova, S. Nagorny, S. Nisi, F. Petricca, F. Proebst, J. Rothe, V.V. Ryabchenkov, S.E. Sarkisov, D.A. Semenov, K.A. Subbotin, M.V. Trushin, E.V. Unzhakov, E.V. Zharikov, New limits on the resonant absorption of solar axions obtained with a $^{169}$Tm-containing cryogenic detector, European Physical J. C 80 (2020) 5, 376.
        Speaker: Alexander Derbin (Petersburg Nuclear Physics)
      • 7:00 PM
        Approach to scaling in axion string networks 5m
        Speaker: Asier Lopez-Eiguren (Tufts University)
      • 7:05 PM
        NuSTAR limits on the solar axion 5m
        Speaker: Crystal Kim (University of California Santa Cruz)
      • 7:10 PM
        Global magnetic field signal of dark-photon dark matter 5m
        Speaker: Saarik Kalia (Stanford University)
      • 7:15 PM
        Constraints on ALPs-Lepton coupling via BBN 5m
        Speaker: Divya Sachdeva (Indian Institute of Science Education and Research)
    • 1:00 PM 2:30 PM
      Session 5
      Convener: Prof. Sungwoo Youn (IBS/CAPP and UST)
      • 1:00 PM
        Manifestations of new particles in atomic and underground laboratories experiments 20m

        Interaction between the standard model matter and low mass scalar dark matter field may be presented as variation of the fundamental constant while interaction with an axion-like field leads to oscillating effects of violation of the fundamental symmetries including electric dipole moments. New interactions mediated by hypothetical particles produce effects, which may be observed in atomic experiments. Our aim is to find enhanced effects, perform their calculations, motivate new experiments and provide interpretation of their results.
        Another direction is accurate relativistic atomic many-body calculations of the effects of dark matter produced in underground laboratories. Our recent calculation of the ionization of atoms by absorption of scalar particles gives cross section, which is several orders of magnitude smaller than that calculated by other authors. The reason is that the traditional plain wave approximation for outgoing electron violates orthogonality condition with bound electron wave function. Such plain wave non-relativistic approximation also gives wrong result (strongly underestimate cross section) for electron ionization by WIMP scattering.
        New results of our group on these topics published recently in PRL, PRD, PRA, JHEP and arxiv papers will be presented.

        Speaker: Victor Flambaum (University of New South Wales, School of Physics, Sydney 2052, Australia)
      • 1:20 PM
        Superconducting Cavity for Dark Matter Axion Search. 25m

        A superconducting resonant cavity operational in high magnetic fields is one of the promising ways for enhancing the scanning speed in axion dark matter search. A high-temperature superconductor (HTS) is a natural choice of material for purpose because of its high upper critical field (~ 100 T) and strong vortex pinning characteristics. The deposition, however, of HTS Rare-earth Barium Copper Oxide (ReBCO) in a biaxially-textured form on a curved surface is technically challenging. The IBS Center for Axion and Precision Physics Research (CAPP) in Korea has applied ReBCO tapes to the inner surface of the polygon-shaped resonant cavity to overcome this problem. This talk will show the results from a 2.3 GHz REBCO cavity that maintains a half-million quality (Q) factor in an 8 T magnetic field. The alignment between tapes has been improved compared to the first-generation prototype to enhance the Q factor. The cavity has also been tested with a sapphire rod tuning system utilizing the CAPP-PACE system where a 2.3 GHz Josephson Parametric Amplifier is coupled in the receiver chain. The commissioning results and the plans for further improvements will be presented.

        Speaker: Mr Danho Ahn (KAIST, IBS/CAPP)
      • 1:45 PM
        Direct limits for scalar field dark matter from a gravitational-wave detector 5m
        Speaker: Sander Vermeulen (Cardiff University)
      • 1:50 PM
        Axion Dark matter from Fragmentation 5m
        Speaker: Philip Sørensen (DESY / Uni Hamburg)
      • 1:55 PM
        ALPs as mediators for dark matter: beyond freeze out 5m
        Speakers: Aoife Bharucha, Sophie Mutzel (CPT Marseille)
      • 2:00 PM
        Dark Acoustic Oscillations: Imprints on the Matter Power Spectrum and the Halo Mass Function 5m
        Speaker: Timothée Schaeffer (University of Zurich)
      • 2:05 PM
        Leading Logs in QCD Axion Effective Field Theory 5m
        Speaker: Lennert Thormaehlen
      • 2:10 PM
        LSW experiments in the microwaves 20m

        We propose a variation, based on very low energy and extremely intense photon sources, on the well established technique of Light-Shining-through-Wall (LSW) experiments for axion-like particle and dark photon searches. With radiation sources at 30 GHz, we compute that present laboratory exclusion limits on axion-like particles might be improved by at least four orders of magnitude, for masses ma . 0.01 meV. This could motivate research and development programs on dedicated single-photon sub-THz detectors.

        Speaker: Paolo Spagnolo (PI)
    • 2:30 PM 2:50 PM
      Break 20m
    • 2:50 PM 4:20 PM
      Session 6
      Convener: Marin Karuza (TS)
      • 2:50 PM
        The Gaia space astrometry mission and the structure of our Galaxy 35m

        The European Space Agency's Hipparcos satellite, operated between 1989-93, measured the accurate positions of some 100,000 stars, and its success represented a fundamentally new discipline in space science. Gaia is a vastly more advanced star-mapping satellite, building on Hipparcos, and launched by ESA in 2013. It continues to operate flawlessly today, measuring the distances and space motions of more than two billion stars with extreme accuracy. The talk will very briefly review the two thousand year history of this branch of astronomy, explain why and how these measurements are made from space, and why the measurement of star positions is of such profound scientific importance. It will emphasise the application to the study of the dynamics of our Galaxy, and in particular how this is related to our understanding of cosmological structure (and the existence of dark matter) in the CDM model.

        Speaker: Michael Perryman
      • 3:25 PM
        Gravitational Focusing of Dark Matter Streams in Solar Neighborhood and Implications for Detection 25m

        Cosmological models of dark matter in the galaxy reveal more intricate features than a smooth standard Halo model. One of the features is the existence of numerous fine-grained streams at solar location where these fine-grain streams have very small velocity dispersion owing to the cold non-interacting nature of dark matter. The gravitational focusing of dark matter from the sun and the planets has been explored previously. These studies have shown that a small modulation in dark matter density would result at Earth’s location if velocity profile of dark matter is Maxwellian which is the assumption in the standard Halo model. The semi-analytic models indicate large density enhancement are possible for streams. We advance the studies further by considering full numerical N-body simulations which take into account input from cosmological simulations on streams, consider the cumulative gravitational effects of Sun, Moon, Earth on DM, and include dispersion effects. Density enhancements and inferences for dark matter candidate measurements will be presented.

        Speaker: Abaz Kryemadhi (Messiah University)
      • 3:50 PM
        First test operation of DANCE: Dark matter Axion search with riNg Cavity Experiment 20m

        Dark matter Axion search with riNg Cavity Experiment (DANCE) was proposed. To search for axion-like dark matter, we aim to detect the rotation and oscillation of optical linear polarization caused by axion-photon coupling with a bow-tie ring cavity. DANCE can improve the sensitivity to the axion-photon coupling constant for axion mass $< 10^{-10}$ eV by several orders of magnitude compared to the best upper limits at present. A prototype experiment DANCE Act-1 with a shorter cavity round-trip length of 1 m is underway to demonstrate the feasibility of our method and to investigate possible technical noises. We assembled the optics, evaluated the performance of the cavity, and estimated the current sensitivity. We are now trying to obtain and analyze the data. In this workshop, we will present the principle of DANCE and the status of DANCE Act-1.

        Speaker: Yuka Oshima (University of Tokyo)
      • 4:10 PM
        Search for axion-like particle in B decays at BABAR 5m
        Speaker: Brian Shuve (Harvey Mudd College)
      • 4:15 PM
        New dark photon search with millimeter waves above 20 GHz 5m
        Speaker: Akira Miyazaki (CERN and the University of Manchester)
    • 4:20 PM 4:40 PM
      Break 20m
    • 4:40 PM 6:00 PM
      Session 7
      Convener: Yannis Semertzidis (Brokhaven National Laboratory)
      • 4:40 PM
        Anisotropy in the gamma-ray transparency of the Universe 20m

        The propagation length of high-energy photons through the Universe is limited by e+e− pair production on the extragalactic background radiation. Previous studies reported discrepancies between predicted and observed attenuation, suggesting explanations in terms of new physics. However, these effects are dominated by a limited number of observed sources, while many do not show any discrepancy. Here, we consider the distribution in the sky of these apparently anomalous objects, selected in two very different approaches: the study of unphysical hardenings at distance-dependent energies in deabsorbed spectra of TeV blazars, and the observation of ultra-high-energy air showers from the directions of BL Lac type objects. In both cases, directions to the anomalous sources follow the projected local distribution of galaxies: all the distant sources, contributing to the anomalies, are seen through the local filament. This matches the prediction of the proposed earlier explanation of the anomalies based on mixing of photons with axion-like particles in the filament's magnetic field. For ultra-high energies, this axion interpretation may be tested by the search of primary gamma rays.

        Based on https://arxiv.org/abs/2004.08321 (Eur.Phys.J.C 81 (2021) 264) +updates.

        Speaker: Sergey Troitsky (INR, Moscow)
      • 5:00 PM
        BREAD: Broadband Reflector Experiment for Axion Detection 20m

        We present a novel dish antenna for broadband ~meV-eV range axion and wave-dark matter detection, which allows to utilize state-of-the-art high-field solenoidal magnets. At these masses it is difficult to scale up traditional resonator setups to the required volume. However, at metallic surfaces in a high magnetic field dark matter axions can convert to photons regardless of axion mass. These photons can be successively focused onto a detector (dish antenna concept). In this talk we present progress on BREAD, a dish antenna using a $\sim 10\,{\rm m}^2$ conversion area with a novel rotationally symmetric parabolic focusing reflector designed to take advantage of high-field solenoidal magnets. We discuss viable low-noise photon detectors and show progress towards smaller first stage hidden photon experiments with expected sensitivity to unexplored hidden photon couplings. We estimate sensitivities for future large-scale experiments.

        Speaker: Stefan Knirck (Fermi National Accelerator Laboratory)
      • 5:20 PM
        Limits on oscillating fundamental constants from laser spectroscopy of molecular ensembles 20m

        Oscillations of the fundamental constants are a possible scenario of the effect of quantum fields beyond the Standard Model.

        We report about two molecular spectroscopic experiments to search for small oscillations of the nuclear mass. The experiments consist in the comparison of a laser frequency defined by the length of a resonator, or of an unconstrained frequency, with the resonance frequency of an electronic molecular transition.

        As such, the experiments are sensitive to modulation of the fine-structure constant, of the electron mass, and of the nuclear mass. The latter sensitivity originates from the vibrational contribution to the electronic transition frequency and is of particular interest here.

        We use molecular iodine (I$_2$), interrogated by lasers at 532 nm and 725 nm. Saturation absorption spectroscopy is used to search for modulation in the frequency range 0.1 - 100 kHz, whereas absorption spectroscopy is employed to cover the range 100 kHz - 100 MHz.

        The results of a first data run and the ensuing bounds on the amplitude of modulation of fundamental constants will be presented.

        Speaker: Prof. S. Schiller (Heinrich-Heine-Universität Düsseldorf)
      • 5:40 PM
        KWISP - Latest results on the chameleon hunt at the CAST experiment at CERN 20m

        The KWISP (Kinetic Weakly Interacting Slim Particle) detector is part of the CAST experiment at CERN exploring the dark sector. It utilizes an ultra-sensitive optomechanical force sensor searching for solar chameleons. Chameleons are hypothetical scalar particles postulated as dark energy candidates, which have a direct coupling to matter depending on the local matter density. Considering these characteristics a flux of solar chameleons hitting a solid surface at grazing incidence will, under certain conditions, reflect and exert the equivalent of radiation pressure on the surface. To exploit this trait the KWISP sensor consists of a thin and rigid dielectric membrane placed inside a resonant optical cavity. The detector setup and the latest results will be presented in this talk.

        Speaker: Justin Baier (University of Freiburg)
    • 6:00 PM 6:20 PM
      Break 20m
    • 6:20 PM 7:20 PM
      Session 8
      Convener: Pierre Sikivie
      • 6:20 PM
        Update on the ARIADNE axion experiment 25m

        The Axion Resonant InterAction Detection Experiment (ARIADNE) will search for the QCD axion using a technique based on nuclear magnetic resonance. The aim is to detect an axion-mediated short-range “fifth-force” between laser-polarized 3He nuclei and an unpolarized tungsten source mass. While thus sourcing the axion locally and therefore being independent of cosmological assumptions, the experiment has the potential to probe deep into the theoretically interesting regime for the QCD axion in the mass range of 0.01-10 meV. The experiment requires a low-vibration non-magnetic liquid helium cryostat, superconducting shielding to limit ordinary magnetic noise, and a stable rotary system to modulate the axion-signal from the source mass. In this talk I will discuss the results of tests of several components of the experimental apparatus and describe the next steps for bringing the experiment into its data-taking phase. When taken together with other existing and planned axion efforts, ARIADNE and other searches have the potential to discover the QCD axion over its entire allowed mass range.

        Speaker: Andrew Geraci
      • 6:45 PM
        Making the invisible visible: search for dark photons using a dielectric multilayer haloscope 5m
        Speaker: Laura Manenti (NYUAD)
      • 6:50 PM
        Probing UV-completion in Axion Sector via Gravitational Waves from Pecei-Quinn Phase Transition 5m
        Speaker: Anish Ghoshal (Laboratori Nazionale Frascati - I.N.F.N. & University Roma Tre)
      • 6:55 PM
        Fragmentation of axion-like particles in the early universe 5m
        Speaker: Cem Eröncel (DESY)
      • 7:00 PM
        Strong bound on canonical ultra-light axion dark matter from the Lyman-alpha forest 5m
        Speaker: Keir Rogers (Dunlap Institute, University of Toronto)
    • 1:00 PM 2:30 PM
      Session 9
      Convener: Joerg Jaeckel
      • 1:00 PM
        Probing the axion-photon interaction with QUAX experiment: status and perspectives. 25m

        In the context of unveiling the Dark Matter problem, in recent years the tentative of detecting axions has made its way. QUAX is an haloscope experiment based in Legnaro (INFN-LNL) and Frascati (INFN-LNF), Italy, designed to detect axions through two different interactions with matter: the axion-photon interaction (QUAX-a$\gamma$) and the axion-electron spin interaction (QUAX-ae). Here I present the status of the QUAX-a$\gamma$ experiment, the recent results and its future prospects.

        Recently, QUAX-a$\gamma$ has reached a milestone in the field, operating the haloscope with a JPA at the quantum limit and reaching a sensitivity to the axion QCD band, becoming a competitor experiment in the panorama. This was possible with the haloscope at Legnaro, where a resonant cavity was put in a 8 T magnetic field at a temperature of about 200 mK, while the noise temperature resulted in less than 1 K. This allowed us to put an average upper limit to the axion-photon coupling of $g_{a\gamma\gamma} = 0.766 \times 10^{-13}~$ GeV$^{-1}$ at 90% confidence level, for an axion mass of $m_a=43~\mu$eV.

        A new haloscope is being assembled in Frascati: there, a dilution refrigerator with base temperature of 10 mK is now available, and this will host a 9 T magnet. The R&D of resonant cavities continues to test superconducting materials to build cavities with, as Nb$_{3}$Sn, and also consists in designing a frequency scan scheme. This is possible either with a usual tuning rod inside the cavity, or inserting a multiple cavity in the magnetic field.

        Speaker: Mr Alessio Rettaroli (Istituto Nazionale di Fisica Nucleare)
      • 1:25 PM
        EMC at CERN 25m

        Electromagnetic compatibility EMC) plays a very import role at CERN in order to assure the peaceful "Living together" of many electrical and electronic systems related to the operation of the particle accelerators but also for the physics experiments .As a baseline the European EMC rules have to be applied everywhere and the safety of the personnel has to be strictly assured under all circumstances. However a certain safety margin between emission and susceptibility of electronic equipment in particular physics experiments is not always grated. In this overview talk a number of examples and past experience is discussed and recommendations for future constructions are mentioned

        Speaker: Dr Fritz Fritz Caspers (CERN)
      • 1:50 PM
        Weyl-Invariant Gravity and the Nature of Dark Matter 5m
        Speaker: Meir Shimon (Tel Aviv University)
      • 1:55 PM
        Examining axion-like particles with superconducting radio-frequency cavity 5m
        Speaker: Petr Satunin (Institute for Nuclear Research of RAS (INR RAS))
      • 2:00 PM
        Data analysis pipeline for optomechanical dark matter detectors 5m
        Speaker: Doris Todorović (Department of pyhsics, University of Rijeka)
      • 2:05 PM
        Breakdown of chiral perturbation theory for the axion hot dark matter bound 5m
        Speaker: Gioacchino Piazza (CNRS, IJCLab)
      • 2:10 PM
        Uncertainties of the Solar Axion Flux Computation 20m

        The calculation of the solar axion flux has recently generated much attention due to the upcoming helioscope IAXO, studies of plasmon processes, and in context of the Xenon1T anomaly. It has been realised that axions can be powerful tools for studying solar metal abundances and magnetic fields. However, the feasibility of such studies depends on our ability to accurately predict the solar axion flux. In this talk, I will present an overview of solar models and opacity codes and summarise the statistical and sytematic uncertainties associated with the solar axion flux calculation from Primakoff, ABC, and plasmon interactions. I will discuss how the calculations could be improved futher, e.g. by including electron degeneracy effects. As a direct application, IAXO's ability to distinguish KSVZ benchmark models will be analysed as well as its prospects to tackle the solar abundance problem. I will close with remarks on our study in the context of the ongoing work in the "axion landscape" and briefly report on ongoing research activities in this direction.

        Speaker: Sebastian Hoof (Georg-August-Universität Göttingen)
    • 2:30 PM 2:50 PM
      Break 20m
    • 2:50 PM 4:20 PM
      Session 10
      Convener: Marc Schumann
      • 2:50 PM
        Axion searches in the next ten years 35m

        The axion, originated from the Peccei-Quinn mechanism proposed to solve the strong-CP problem, is one of the most appealing dark matter candidates.
        Since its prediction, there have been various experimental searches based on novel ideas and now is starting to reach theoretically interesting sensitivity levels.
        Enormous progress in a wide range of technologies has also been made to widen the search range as well as to enhance sensitivities.
        The next ten years would be critical to explore a large fraction of the axion parameter space and hence shed light on the two fundamental mysteries in physics.
        We overview of the current status of direct axion search programs and discuss the future prospects.

        Speaker: Prof. Sungwoo Youn (IBS/CAPP and UST)
      • 3:25 PM

        The CAST experiment at CERN was recently converted from axion helioscope to axion haloscope searching for Dark Matter (DM) axions. The CAST-CAPP detector, whose current status and recent results will be presented, consists of four tunable cavities installed inside one of the two twin bores of the CAST dipole magnet. The detector is using the phase-matching technique to improve the signal-to-noise ratio. In addition to searches for galactic axions, the CAST-CAPP detector has the potential to search for streaming DM axions including the theoretically motivated axion mini-clusters. The currently excluded frequency range for virialized axionic dark matter extends over a range of ~660MHz corresponding to axions with masses around 19.7 – 22.4 μeV and sets a competitive limit.

        Speaker: Marios Maroudas (University of Patras)
      • 3:50 PM
        Solar Magnetism: From the Generation, over their Importance to the Measuring Techniques of Solar Magnetic Fields 25m

        In this talk we will outline the basic idea of the generation of solar magnetic fields via an acting global solar dynamo, highlight the importance of the solar magnetic fields for our understanding of the dynamic phenomena within the solar atmosphere as well as their influence on the observed space weather.

        Moreover we will have a look into the spatial high resolution end of observations of small-scale dynamic fields and have a first glimpse on the techniques and instrumentation to observe magnetic fields on the Sun.

        Speaker: Dr Dominik Utz (Kepler University Hospital (1), Instituto de Astrofísica de Andalucía (2))
      • 4:15 PM
        Strong magnetic field operation of a very high Q-factor dielectric microwave resonator for axion dark matter search 5m
        Speaker: Raffaele Di Vora (Istituto Nazionale di Fisica Nucleare)
    • 4:20 PM 4:40 PM
      Break 20m
    • 4:40 PM 6:00 PM
      Session 11
      Convener: Abaz Kryemadhi (Messiah University)
      • 4:40 PM
        Observation of Excess Electronic-Recoil Events in XENON1T 25m

        We present evidence for excess low-energy interactions in the XENON1T detector and discuss possible interpretations. Using a 0.65 t yr exposure, we perform one of the most sensitive searches for solar axions, an enhanced neutrino magnetic moment using solar neutrinos, and bosonic dark matter. We observe an excess of low-energy (1—7 keV) events. A solar axion signal is favoured at 3.4σ over background, and the signal can also be explained by the beta-decay of tritium within the detector or by an enhanced neutrino magnetic moment.

        Speaker: Adam Brown (University of Freiburg)
      • 5:05 PM
        Axion Quark Nuggets and Matter-Antimatter asymmetry as two sides of the same coin: theory, observations and future experimental searches 25m

        In this talk I want to discuss the (unorthodox) scenario when the baryogenesis is replaced by a charge segregation process in which the global baryon number of the Universe remains zero. In this, the so-called axion quark nugget (AQN) dark matter model the unobserved antibaryons come to comprise the dark matter in the form of dense nuggets. In this framework, both types of matter (dark and visible) have the same QCD origin, form at the same QCD epoch, and both proportional to one and the same fundamental dimensional parameter of the system, which explains how the two, naively distinct, problems could be intimately related, and could be solved simultaneously within the same framework. I specifically focus on several recent papers written with AMO (Atomic-Molecular-Optic), Nuclear physics and Astro-physics people to apply these generic ideas to several recent proposals: 1. on broadband strategy in the axion searches; 2. on daily modulations and amplifications generated by the AQN dark matter and how they can be studied; 3. on recently detected by Telescope Array the Mysterious Burst Events which are very distinct from conventional cosmic air showers.

        The talk is based on several recent papers including:

        1.D.Budker, V.V.Flambaum, X.Liang and A.Zhitnitsky,
        Axion Quark Nuggets and how a Global Network can discover them,'' Phys. Rev. D 101 no.4, 043012 (2020) [arXiv:1909.09475 [hep-ph]].\\ 2. A.~Zhitnitsky,The Mysterious Bursts observed by Telescope Array and Axion Quark Nuggets,''
        Journal of physics G: Nuclear and Particle Physics (2021) [arXiv:2008.04325 [hep-ph]]

        Speaker: Ariel Zhitnitsky (University of British Columbia)
      • 5:30 PM
        Superconducting Qubit Advantage for Dark Matter (SQuAD) 5m
        Speaker: Ankur Agrawal
      • 5:35 PM
        Astrophysical hints for magnetic black holes 5m
        Speaker: Farman Ullah Sheikh
      • 5:40 PM
        Overview and Status of the LUX-ZEPLIN Experiment 20m

        The LUX-ZEPLIN (LZ) detector consists of a dual-phase xenon time projection chamber designed to directly detect Weakly Interacting Massive Particles (WIMPs) with unprecedented sensitivity, down to a WIMP-nucleon spin-independent cross section of 1.4 x 10^-48 cm^2 for a 40 GeV/c^2 mass in 1000 live days. The experiment is currently in its commissioning phase, with science running expected to begin later this year. This talk will give an overview of the project, and report on its current status.

        Speaker: Amy Cottle (University of Oxford)
    • 6:00 PM 6:20 PM
      break 20m
    • 6:20 PM 7:25 PM
      Session 12
      Convener: Giovanni Cantatore (TS)
      • 6:20 PM
        Dark Photon Limits: a Cookbook 20m

        The dark photon is a massive hypothetical particle that interacts with the Standard Model by kinetically mixing with the visible photon. Due to the similarity with the electromagnetic signals generated by axions, many putative bounds on dark photon signals are simply reinterpretations of historical bounds set by axion haloscopes. However, the dark photon has a property that the axion does not: an intrinsic polarization. Due to the rotation of the Earth, accurately incorporating this polarization into dark photon analyses is nontrivial, and highly experiment-dependent. Several well-known searches for axions employ techniques for testing signals that preclude their ability to set exclusion limits on dark photons, and hence should not be reinterpreted as such. Most experiments do not have a straight forward reinterpritation for polarized dark photons. On the other hand, we find that if one does account for the dark photon's polarization, and the rotation of the Earth, the theoretical sensitivity to the dark photon's kinetic mixing parameter can be improved by over an order of magnitude. Here, we detail the strategies that would need to be taken to properly optimise a dark photon search. These include a judiciously choosing the orientation of the experiment, as well as strategically timing any repeated measurements and splitting measurements into multiple parts. Such strategies have significant impact on limits without additional time or cost.

        Speaker: Alexander Millar (Stockholm University)
      • 6:40 PM
        HiRes Analysis of the ADMX Run 1c Data 20m

        The Axion Dark Matter Experiment (ADMX) aims to detect the decay of axions in the galactic halo into two microwave photons within a cavity. There are two main analysis channels for the experiment. One has a frequency resolution of 200 Hz and is called medium res. The second has a frequency resolution of 20 mHz and is called HiRes. The latest data taken was for run 1c., which uses a single cavity covering a frequency range of approximately 800 MHz to 1 GHz. This frequency range corresponds to an axion mass between 3.3-4.1 μeV. We will present our objectives for the analysis along with our methods. Further, we will discuss future plans for the high resolutiong analysis team. *This work was supported by the U.S. Department of Energy through Grants No DE-SC0009800, No. DE-SC0009723, No. DE-SC0010296, No. DE-SC0010280, No. DE-SC0011665, No. DEFG02-97ER41029, No. DE-FG02-96ER40956, No. DEAC52-07NA27344, No. DE-C03-76SF00098 and No. DE-SC0017987. Fer-milab is a U.S. Department of Energy, Office of Science, HEP User Facility. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract No. DE- AC02-07CH11359. Additional support was provided by the Heising-Simons Foundation and by the Lawrence Livermore National Labora-tory and Pacific Northwest National Laboratory LDRD offices.

        Speaker: Alexander Hipp
      • 7:00 PM
        Recent results from the Chandra analysis 25m

        Axions may be produced in abundance within compact stars such as white dwarfs and neutron stars. It has long been recognized that axion production in compact stars opens up a new pathway for them to cool. I will point out, however, that axions may also lead to novel X-ray signatures around these stars, whereby the axions are produced within the stellar cores and then convert to photons in the strong magnetic fields surrounding the stars. I will discuss recent data taken by the XMM-Newton and Chandra telescopes from nearby neutron stars and white dwarfs that provide some of the strongest probes to-date of axions by searching for these processes. In particular, I will focus on the analysis of 40 ks of dedicated Chandra data taken in late 2020 towards the magnetic white dwarf RE J0317-853.

        Speaker: Benjamin Safdi
    • 1:00 PM 2:30 PM
      Session 13
      Convener: Horst Fischer
      • 1:00 PM
        Searching for dark matter using precision oscillators 25m

        We present recent result that search for Dark Matter using precision oscillators. the first experiment searches for scalar dark matter via Coupling to Fundamental Constants through the comparison of photonic, atomic and mechanical oscillators. Specifically we compare a cryogenic sapphire oscillator (CSO), hydrogen maser (HM) atomic oscillator, and a bulk acoustic wave quartz oscillator (OCXO). This work includes the calculation of the dependence of acoustic oscillators on variations of the fundamental constants, and demonstration that they can be a sensitive tool for scalar DM experiments. Results are presented based on 16 days of data in comparisons between the HM and OCXO, and 2 days of comparison between the OCXO and CSO. No evidence of oscillating fundamental constants consistent with a coupling to scalar dark matter is found, and instead limits on the strength of these couplings as a function of the dark matter mass are determined, and is described in detail in [1]. The second experiment involves searching for frequency shifts between two cylindrical cavity modes, which up converts any low mass axion signal to microwave frequencies, a proof of principle experiment was undertaken and will also be discussed. To improve these experiments, new ways to build ultra-low phase noise oscillators are under development [3], and should significantly advance these experiment in the future.
        [1] WM Campbell, BT McAllister, M Goryachev, EN Ivanov, ME Tobar, Phys. Rev. Lett. vol. 126, 071301, 2021.
        [2] CA Thomson, BT McAllister, M Goryachev, EN Ivanov, ME Tobar, Phys. Rev. Lett., vol., 126, 081803, 2021.
        [3] EN Ivanov, ME Tobar,"Noise Suppression with Cryogenic Resonators," IEEE Microwave and Wireless Components Letters, vol. 31, no. 4, 2021.

        Speaker: Prof. Michael Tobar (The University of Western Australia)
      • 1:25 PM
        DFSZ axion definitive searches at IBS/CAPP 25m

        The CAPP-12TB experiment is a resonant microwave cavity axion search at IBS/CAPP in KAIST for the axion mass range 3.3 - 12.4 μeV. All parts of the system are currently being integrated to begin the first phase of the experiment. The system consists of a superconducting solenoid with a bore size of 320 mm that has been tested to reach a maximum field of 12 T, a cryogenic dilution fridge with physical temperatures around 50 mK with the cavity load, and a nearly quantum-limited noise Josephson parametric amplifier. The copper cavity has a large volume (30 L) and a measured Q-factor above a hundred thousand along most of its frequency range tuned by a copper rod. An asymmetric design is introduced in order to resolve the issue of so-called mode mixings - mixture of the desired resonant mode with unwanted modes during the frequency tuning process. The experiment expects to explore the mass range with sensitivity beyond the DFSZ level within a few years.

        Speaker: Andrew Kunwoo Yi (Korea Advanced Institute of Science and Technology)
      • 1:50 PM
        The ORGAN Experiment: Current Status, and Future Plans 20m

        We present the current status, and future plans of The Oscillating Resonant Group AxioN (ORGAN) Experiment, a high-mass (∼60−200 𝜇eV) microwave cavity axion haloscope hosted at the University of Western Australia. ORGAN comprises various phases and sub-phases, having commenced in 2021, and running until 2026. We will discuss each phase, their experimental details, and projected reach. We will report the results of Phase 1a, which commenced in 2021, and the status of phase 1b, which will commence in late 2021/early 2022. Initial phases rely on traditional tuning-rod resonators, and HEMT amplifiers. Future phases project the use of novel resonant designs based on dielectric structures, and advanced readout techniques based on GHz single photon counters (SPCs). We will discuss the proposed resonant designs, and report on progress in the development of SPCs. It is projected that, with the development of efficient SPCs, within the 12+ Tesla, milli-Kelvin environment of ORGAN, DFSZ sensitivity is attainable over the entire mass range within the time-scale of the experiment.

        Speaker: Ben Mcallister (Quantum Technology and Dark Matter Laboratory, Physics Department, University of Western Australia)
      • 2:10 PM
        A search for unvirialized axions in ADMX run 1b 5m
        Speaker: Dr Shriram Jois
      • 2:15 PM
        Search for Axion domain walls using the Global Network of Optical Magnetometers for Exotic physics (GNOME)¹ 5m
        Speaker: Hector Masia Roig (Johannes Gutenberg Universität Mainz)
      • 2:20 PM
        Coannihilating Dark Matter and the B-Physics Anomalies 5m
        Speaker: Sokratis Trifinopoulos (Istituto Nazionale di Fisica Nucleare)
      • 2:25 PM
        Thermal axions with multi-eV masses are possible in low-reheating scenarios 5m
        Speaker: Pierluca Carenza (Istituto Nazionale di Fisica Nucleare)
    • 2:30 PM 2:50 PM
      Break 20m
    • 2:50 PM 4:20 PM
      Session 14
      Convener: Wolfgang Funk
      • 2:50 PM
        Status of CASPEr-gradient and study of its quantum sensitivity limits 35m

        The cosmic axion spin precession experiment (CASPEr) is a nuclear magnetic resonance experiment to search for axion and axion-like particles (ALPs) that possibly make up a significant portion of dark matter in the Universe [1,2]. Due to the pseudoscalar nature and the light mass of ALPs, they can be treated as a field exerting a time-varying torque on nuclear spins either directly or through the generation of an oscillating nuclear electric dipole moment. In CASPEr-gradient, a sample of nuclear spins is placed in a magnetic field which is tunable over a wide range, thereby changing the Larmor frequency. When the Larmor frequency approaches the Compton frequency of the ALP, a magnetization will build up which we intend to detect using superconducting quantum interference devices (SQUIDs). We are currently characterizing the performance of the setup by measuring spin-projection noise of protons. Recently, we showed how this noise source together with thermal and amplifier noise is expected to present itself in our search for ALPs [3]. We found that suppression of the circuit back-action will be especially important in order for the spin-projection noise limits of searches for axion-like dark matter to reach the quantum chromodynamic axion sensitivity.

        [1] D. Budker, P. W. Graham, M. Ledbetter, S. Rajendran, and A. O. Sushkov, Proposal for a Cosmic Axion Spin Precession Experiment (CASPEr), Phys. Rev. X 4, 021030 (2014).
        [2] D. F. Jackson Kimball, S. Afach, D. Aybas, J. W. Blanchard, D. Budker, G. Centers, M. Engler, N. L. Figueroa, A. Garcon, P. W. Graham, H. Luo, S. Rajendran, M. G. Sendra, A. O. Sushkov, T. Wang, A. Wickenbrock, A. Wilzewski, and T. Wu, Overview of the Cosmic Axion Spin Precession Experiment (CASPEr), in Microwave Cavities and Detectors for Axion Research, edited by G. Carosi and G. Rybka (Springer International Publishing, Cham, 2020), pp. 105–121.
        [3] D. Aybas, H. Bekker, J. W. Blanchard, D. Budker, G. P. Centers, N. L. Figueroa, A. V. Gramolin, D. F. J. Kimball, A. Wickenbrock, and A. O. Sushkov, Quantum Sensitivity Limits of Nuclear Magnetic Resonance Experiments Searching for New Fundamental Physics, ArXiv:2103.06284 [Cond-Mat, Physics:Hep-Ph, Physics:Physics, Physics:Quant-Ph] (2021).

        Speaker: Hendrik Bekker (Johannes Gutenberg University of Mainz)
      • 3:25 PM
        Searches for high frequency axions at IBS/CAPP 25m

        Multiple-cell cavities were designed by IBS/CAPP to access high frequency regions while maximally utilizing the volume of a given solenoid for cavity haloscopes. We conducted the first multiple-cell haloscope experiment, CAPP-9T MC, using a double-cell cavity mounted in JANIS He-3 cryogenic system equipped with a 9T superconducting magnet. We obtained a new limit for $g_{a\gamma\gamma}$ that is about 5 times better than the previous limit over the axion mass range between 13$\,\mu$eV and 13.9$\,\mu$eV from data acquired for about 19 days. The experiment has successfully demonstrated that this unique cavity design is capable of exploring high frequency regions more efficiently. IBS-CAPP plans to install quad-cell, sext-cell, and octa-cell cavities to search for axions at even higher frequencies in the near future.

        Speaker: Junu Jeong (IBS/CAPP)
      • 3:50 PM
        Dark Matter Scattering in Optomechanical Experiments 20m

        We will discuss our recent work on the possibility to look for dark matter scattering at gravitational wave detectors and optomechanical setups in general. For particle dark matter this should induce an effect very similar to Brownian motion. We will present results from a particle physicist's and a gravitational wave astronomer's point of view.

        Speaker: Prof. Martin Spinrath (National Tsing Hua University (NTHU))
      • 4:10 PM
        Searching for axion-like dark matter with CASPEr-electric 5m
        Speaker: Deniz Aybas (Boston University)
    • 4:20 PM 4:40 PM
      Break 20m
    • 4:40 PM 5:55 PM
      Session 15
      • 4:40 PM
        Overview of DAMIC and its upgrade DAMIC-M 25m

        The DAMIC experiment at SNOLAB uses thick, fully-depleted, scientific grade charge-coupled devices (CCDs) to search for the interactions between proposed dark matter particles in the galactic halo and the ordinary silicon atoms in the detector. DAMIC CCDs operate with an extremely low instrument noise and dark current, making them particularly sensitive to ionization signals expected from low-mass dark matter particles. For the past two years, DAMIC has collected dark-matter search data with an array of seven CCDs (40-gram target) installed in a low radiation environment in the SNOLAB underground laboratory. This talk will focus on the recent dark matter search results from DAMIC. We will present the search methodology and results from an 11 kg day exposure WIMP search, including the strictest limit on the WIMP-nucleon cross section for a silicon target for 𝑚𝜒<9 GeV c−2. Additionally, We will present the upgrade of this detector, a kg-size detector will be installed at the Laboratoire Souterrain de Modane in France. DAMIC-M (DAMIC at Modane) will combine the excellent understanding of CCD backgrounds from DAMIC at SNOLAB with ongoing developments in the single-electron resolution of Skipper amplifiers to provide unprecedented sensitivity to light dark matter particles. The DAMIC-M program takes advantage of the unparalleled capability to reject events from radioactivity in the CCDs by exploiting spatial coincidences within a decay chain over timescales as long as months. This, combined with aggressive controls over detector design and material selection, will allow DAMIC-M to probe new models of light dark matter.

        Speaker: Nuria Castello Mor (University of Cantabria)
      • 5:05 PM
        Dark Sector Searches with the NA64 Experiment at CERN 20m

        The existence of dark sectors is an exciting possibility to explain the origin of Dark Matter (DM). In particular, a class of phenomenological models assumes the existence of a vector portal, through which the dark sector and visible matter are related by a new force, in addition to gravity, transmitted by a light dark vector boson, $A'$ (dark photon). Within this class of models, DM interacts with Standard Model (SM) particles through kinetic mixing of the $A'$ with the SM photon, $\gamma-A'$, with a mixing strength $\epsilon\ll1$. If $A’$ exists, it could be produced through the kinetic mixing with a bremsstrahlung photon from a high-energy electron scattering in a target. $A’$ could then decay invisibly into light DM particles, $A’\rightarrow\chi\chi$, or visibly, into $e^+e^-$. Searching for the former in events with large missing energy allows to probe the $\gamma-A'$ mixing strength and the parameter space close to the one predicted by the relic dark matter density. Motivation for searching visible decays has been recently enhanced by the anomaly observed in the $^8$Be and $^4$He nuclei transitions that could be explained by the existence of a 17 MeV boson also decaying into $e^+e^-$. In this talk, we present the latest NA64 results from the combined 2016-2018 data analysis for visible and invisible modes, and, with the end of the CERN long shutdown (LS2), the future prospects for the 2021 run. New recent results on axionlike and scalar particles searches produced though Primakoff reaction will also be discussed. Finally, with the recent announcement of the Fermilab latest result on the muon anomalous magnetic moment, prospects in the search for dark sectors weakly coupled to muon through the NA64 muon program, recently approved, will be presented.

        Speaker: Henri Sieber (ETH Zürich)
      • 5:25 PM
        Observation of Thermal Photons from the 14 GHz Cavity by a Single-Photon Counter within the QUAX 5m
        Speaker: Leonid Kuzmin (Chalmers University of Technology)
      • 5:30 PM
        Unitarity and Higher-Order CP Asymmetries - A Systematic Perturbative Approach 5m
        Speaker: Peter Matak (Comenius University in Bratislava, Slovak Republic)
      • 5:35 PM
        Observing Invisible Axions with Gravitational Waves 20m

        Axions are among the best motivated candidates for new physics. If the Peccei-Quinn symmetry associated with an axion has been ever restored after inflation, topological defects of the axion field (in particular strings) form and produce an irreducible contribution to the stochastic gravitational wave background during the evolution of the Universe. After reviewing recent progress in the understanding of the dynamics of such objects, I will discuss the resulting gravitational wave spectrum by combining effective field theory analysis with the numerical evolution of the field theory equations. I will show that a single ultralight axion-like particle with a decay constant larger than $10^{14}$ GeV and any mass between $10^{-18}$ and $10^{-28}$ eV leads to an observable gravitational wave spectrum, and is compatible with constraints from dark matter overproduction, isocurvature and dark radiation. Crucially, the spectrum extends over a wide range of frequencies and the resulting signal could be detected by multiple experiments. I will also comment on the recent possible NANOgrav signal in light of these results.

        Speaker: Marco Gorghetto (Weizmann Institute)
    • 5:55 PM 6:15 PM
      Break 20m
    • 6:15 PM 7:35 PM
      Session 16
      Convener: Prof. Paola Arias Reyes
      • 6:15 PM
        Status of baby-IAXO 25m

        The International Axion Observatory, IAXO is a large-scale axion helioscope that will look for axions and axion-like particles (ALPs), produced in the Sun and it is conceived to reach a sensitivity on the axion photon coupling in the range of 10-12 GeV-1. On the way to IAXO, a smaller experiment baby-IAXO is in the construction phase. Baby-IAXO will be important to test all IAXO subsystems (magnet, optics and detectors) and at the same time, as a fully-fledged helioscope, will reach a sensitivity on the axion-photon coupling of 1.5·10-11 GeV-1 for masses up to 0.25 eV, covering a very interesting region of the parameter space. Important milestones have been reached in the past years in the development of the different components of the experiment as low background x-ray detectors and x-ray optics as well as for the large magnet and the mechanical infrastructures. We report on the development of the x-ray photon detection instruments and on the construction of the baby-IAXO magnet. Finally, we discuss the schedule for seeing the first light in baby-IAXO in 2024.

        Speaker: Elisa Ruiz Chóliz (Johannes Gutenberg University Mainz)
      • 6:40 PM
        Heterodyne Detection of Axion Dark Matter in an RF Cavity 20m

        I will present a recently proposed approach to detect photon-coupled dark matter axions in an RF cavity. The approach relies on axion-mediated transitions between nearly-degenerate resonant modes, leading to parametrically enhanced signal power for light axions. We will discuss how a resonant signal is generated, and how it compares with traditional haloscope searches. We will also discuss noise sources. This approach could probe axion masses across fifteen orders of magnitude, all in a metre-scale cavity.
        Time permitting, I will comment on the applicability of a similar apparatus for gravitational wave detection.

        Speaker: Sebastian Ellis
      • 7:00 PM
        Search for axion-like dark matter with ferromagnets 20m

        Ultralight axion-like particles are well-motivated dark matter candidates, emerging naturally from theories of physics at ultrahigh energies. We report the results of the Search for Halo Axions with Ferromagnetic Toroids (SHAFT) - a direct search for the electromagnetic interaction of axion-like dark matter in the mass range that spans three decades from 12 peV to 12 neV [1]. The detection scheme is based on a modification of Maxwell's equations in the presence of axion-like dark matter, which mixes with a static magnetic field to produce an oscillating magnetic field. The experiment makes use of toroidal magnets with iron-nickel alloy ferromagnetic powder cores, which enhance the static magnetic field by a factor of 24. Using SQUIDs, we achieve a magnetic sensitivity of $150\,\text{aT}/\sqrt{\text{Hz}}$, at the level of the most sensitive magnetic field measurements demonstrated with any broadband sensor. We recorded 41 hours of data and placed new limits on the magnitude of the axion-like dark matter electromagnetic coupling constant over part of our mass range, at 20 peV reaching $4.0 \times 10^{-11}~\text{GeV}^{-1}$ (95\% confidence level). Our measurements are starting to explore the coupling strengths and masses of axion-like particles where mixing with photons could explain the anomalous transparency of the universe to TeV gamma-rays.

        [1] Alexander V. Gramolin, Deniz Aybas, Dorian Johnson, Janos Adam & Alexander O. Sushkov, ”Search for axion-like dark matter with ferromagnets”, Nature Physics 17, 79-84 (2021).

        Speaker: Alexander Sushkov (Boston University)
      • 7:20 PM
        Recent Hidden Sector Searches at BABAR 5m
        Speaker: Brian Shuve (Harvey Mudd College)
      • 7:25 PM
        Controlling relaxation of nuclear spin qubit ensembles for a more sensitive search for axion-like dark matter 5m
        Speaker: Janos Adam
      • 7:30 PM
        Inflating the Universe With Light Dark Sector and Conformal Invariance 5m
        Speaker: Anish Ghoshal (Laboratori Nazionale Frascati - I.N.F.N. & University Roma Tre)
    • 1:00 PM 2:30 PM
      Session 17
      Convener: Michael Tobar (The University of Western Australia)
      • 1:00 PM
        (Halo) Scoping out the Parameter Space of Wave-Like Dark Matter 25m

        The scope of the dark matter problem is profound, with 85% of all matter existing in some unknown form. In the case of the axion, the challenge is compounded by the fact that the parameter space is largely unexplored. The Axion Dark Matter eXperiment (ADMX) and other resonant searches are tackling this problem by searching for axions using a microwave cavity in a magnetic field. We report on recent headway made by ADMX into the parameter space for the QCD axion, and lay out plans to move upwards in frequency (mass) space using multi-cavity arrays. Recent technological advancements in quantum technology and elsewhere have enabled improvements in the scan speed and sensitivity of resonant cavity haloscopes. We cover the implications of such technology in these experiments, as well as novel analysis techniques. A variety of ideas will be presented on the topic of joint efforts from cavity haloscope groups to improve both the sensitivity as well as the mass coverage of these experiments, especially as we move towards higher frequencies.

        Speaker: Chelsea Bartram (University of Washington)
      • 1:25 PM
        MADMAX - Towards a Dielectric Axion Haloscope 25m

        The MAgnetized Disc And Mirror Axion eXperiment is designed to search for dark matter axions in the mass range of 40 to 400 µeV, a range previously inaccessible by other experiments. This mass range is favored by models in which the PQ symmetry is broken after inflation. The required sensitivity is reached in MADMAX by applying the dielectric haloscope approach, exploiting the axion to photon conversion at dielectric surfaces within a strong magnetic field. For MADMAX a system of 80 movable dielectric discs of 1.25 m diameter, the so-called booster, inside an approximately 9 T magnetic field is foreseen. The experiment will be located at DESY Hamburg in Germany and is currently entering its prototyping phase.

        One of the important steps on the path towards the MADMAX prototype is of course the understanding and calibration of the booster and its behavior which is currently persued using small scale closed systems. Vast progress has been made here in the last year, but also in the design of prototype booster and testing of its components as well as in the preparations for an operation of the MADMAX prototype inside the MORPURGO magnet at CERN allowing for an Axion-Like-Particle search as a first physics run with the prototype.

        In this contribution, results from the small scale closed booster system, showing good agreement between simulation and measurement, will be shown along with the results of extensive simulation studies looking at various aspects of the prototype and full-scale booster. Also, the advanced design of the prototype booster including test results on the newly developed piezo based drive system for the dielectric discs will be presented. Together with all these results guiding the path towards the MADMAX (prototype) experiment an outlook will be given on the time schedule for the MADMAX prototype including the operation and the planned ALPs search at CERN as well as on ongoing developments such as future low noise receivers.

        Speaker: Christoph Krieger (Universität Hamburg)
      • 1:50 PM
        SIS junction as single microwave photon detector for axion search 5m
        Speaker: Dr Andrey Pankratov (Nizhny Novgorod State Technical University, RF)
      • 1:55 PM
        Isotropic Cosmic Birefringence Signals from Axion-like Dark Matter 5m
        Speaker: Pranjal Trivedi (University of Hamburg)
      • 2:00 PM
        Axion quality from gauge flavour symmetries 5m
        Speaker: Enrico Nardi (LNF)
      • 2:05 PM
        Probing axion-like particle radiation from primordial black holes 5m
        Speaker: Francesco Schiavone
      • 2:10 PM
        Quark nugget models of dark matter revisited 20m

        We revisit models of quark matter as possible candidates for dark matter. In these models, dark matter may consist of compact composite objects of dense quark (or antiquark) matter which we refer to as the quark nuggets (QN). We focus on the properties of the electron (or positron) cloud around the QN core, because it may play a crucial role in dark matter detection experiments. In particular, we study the electron (or positron) density distribution, electron-positron annihilation, photon absorption length and thermal radiation in the electron (or positron) cloud. We also discuss the quark-antiquark annihilation of ordinary matter in the QN core and its products. These processes specify the radiation spectrum from the quark nuggets in space and when they hit the Earth and possibilities of QN detection.

        Speaker: Igor Samsonov (The University of New South Wales)
    • 2:30 PM 2:50 PM
      Break 20m
    • 2:50 PM 4:10 PM
      Session 18
      Convener: Laura Baudis (University of Zurich)
      • 2:50 PM
        WIMP Direct Detection -- Experimental Status and Outlook 2021 35m

        Nowadays, we have a highly accurate model of our Universe, but still, most of its content eludes our observation. The experimental efforts to decipher the nature of dark matter underwent amazing development in recent years. A new generation of large exposure high sensitivity detectors is ready to accept the challenge. In this contest, a multi-target multi-technology approach is needed to look into the different mass regions of possible dark matter candidates to maximise the detection probability. The most sensitive techniques opening new frontiers of this search will be reviewed together with a glance on future perspectives.

        Speaker: Federica Petricca (Max-Planck-Institut für Physik)
      • 3:25 PM
        Search for sterile keV neutrinos 20m

        Sterile neutrinos appear in minimal extensions of the Standard Model of particle physics. If their mass is in the keV regime, they are viable dark matter candidates. In this talk both indirect astrophysical and cosmological limits and new ideas for laboratory-based searches will be presented. Special focus will be put on a possible future upgrade of the KATRIN experiment with a novel multi-pixel detector system, which would allow to search for the characteristic signature of sterile neutrinos in tritium beta decay.

        Speaker: Thibaut Houdy (Max Planck for Physics, Munich)
      • 3:45 PM
        The spectral lineshape of gradient-coupled bosonic dark matter in our galaxy 20m

        Virialized bosonic dark matter in our galaxy features a distinct spectral lineshape due to the velocity distribution of its constituents. If it can be resolved in an experiment, its expected evolution during Earth's propagation through the galaxy is a useful systematic check in case of a positive detection and can be used via pattern search algorithms to improve the sensitivity to galactic dark matter in haloscope experiments. If it cannot be resolved the underlying probability density function informs the exclusion power of a given data set. The lineshape depends on the type of interaction between the dark matter and the experimental apparatus. Most of the searches until now have been sensitive to the scalar coupling, for which the lineshape is known. We derive the spectral lineshape of gradient-coupled bosonic dark matter, illustrate differences to scalar coupled experiments and point at novel signatures to search for.

        Speaker: Arne Wickenbrock (Johannes Gutenberg University Mainz)
    • 4:10 PM 4:30 PM
      Break 20m
    • 4:30 PM 5:40 PM
      Session 19
      Convener: Joerg Jaeckel
      • 4:30 PM
        Axion Quasiparticles for Axion Dark Matter Detection 25m

        It has been suggested that certain antiferromagnetic topological insulators contain axion quasiparticles (AQs), and that such materials could be used to detect axion dark matter (DM). I review recent progress in this direction. I begin by clarifying the effective theory, and introducing a model for material losses. Current progress on measurement of material candidates is discussed. The resonance mechanism is explained following the principle of the dielectric haloscope. AQ-photon mixing leads to an effective photon mass, changing the optical properties of the material, and allowing for resonant axion DM-photon conversion in samples large compared to the axion Compton wavelength. The proposal could allow for detection of axion DM in the mass range between 1 and 10 meV.

        Speaker: David Marsh (King's College London)
      • 4:55 PM
        Photophilic hadronic axion from heavy magnetic monopoles 20m

        We propose a model for the QCD axion which is realized through a coupling of the Peccei-Quinn scalar field to magnetically charged fermions at high energies. We show that the axion of this model solves the strong CP problem and then integrate out heavy magnetic monopoles using the Schwinger proper time method. We find that the model discussed yields axion couplings to the Standard Model which are drastically different from the ones calculated within the KSVZ/DFSZ-type models, so that large part of the corresponding parameter space can be probed by various projected experiments. Moreover, the axion we introduce is consistent with the astrophysical hints suggested both by anomalous TeV-transparency of the Universe and by excessive cooling of horizontal branch stars in globular clusters. We argue that the leading term for the cosmic axion abundance is not changed compared to the conventional pre-inflationary QCD axion case for axion decay constant $f_a > 10^{12}~\text{GeV}$.

        Speaker: Anton Sokolov (DESY)
      • 5:15 PM
        Catching the axion via new CP-violating forces 20m

        While the axion was originally introduced to "wash out" CP violation from strong interactions, new sources of CP violation beyond QCD (needed e.g. for the matter-antimatter asymmetry) might manifest themselves via a tiny scalar axion-nucleon component. The latter can be experimentally probed in axion-mediated force experiments, as suggested long ago by J.E. Moody and F. Wilczek. In the present contribution, I will review this story and report on a recent calculation of the scalar axion-nucleon coupling based on chiral Lagrangian techniques, correcting and expanding on previous works.

        Speaker: Luca Di Luzio (Istituto Nazionale di Fisica Nucleare)
      • 5:35 PM
        Results of axion searches at 34 μeV with RADES haloscope and prospects for searches in BabyIaxo 5m
        Speaker: Sergio Arguedas Cuendis
    • 5:40 PM 6:00 PM
      Break 20m
    • 6:00 PM 6:40 PM
      Session 20
      Convener: Axel Lindner (DESY)
      • 6:00 PM
        ALPHA: The Axion Longitudinal Plasma HAloscope Consortium 20m

        In 2019 we introduced a new strategy to search for dark matter axions using tunable cryogenic plasmas. Unlike current experiments, which repair the mismatch between axion and photon masses by breaking translational invariance (cavity and dielectric haloscopes), a plasma haloscope enables resonant conversion by matching the axion mass to a plasma frequency. A key advantage is that the plasma frequency is unrelated to the physical size of the device, allowing large conversion volumes. We here summarize our progress towards realizing this detection scheme, and introduce a global consortium of researchers working towards making the plasma haloscope a reality.

        Speaker: Matthew Lawson (Stockholm University)
      • 6:20 PM
        CYGNO – A 3D Optical Readout TPC for Directional Dark Matter Searches 20m

        The CYGNO project has the goal to use a gaseous TPC with optical readout for low-energy directional Dark Matter search and solar neutrinos detection, providing a unique way to explore their nature.

        The CYGNO demonstrator will consist of 1 m3 active volume in 50 cm drift back-to-back TPC, filled with He-CF4 gas mixture at atmospheric pressure, to be installed at the underground facilities of the Laboratori Nazionali del Gran Sasso (Italy). The unique combination of the TPC characteristics with the high-granularity sCMOS and fast sensors, used for reading out the light produced in the amplification stage (made of a triple-GEM structure), provides not only a detailed reconstruction of the event topology and energy, but also an excellent directional and head-to-tail capability. Thus, resulting in a promising particle identification / discrimination capability, essential to distinguish events taking place inside the active volume of the detector.

        Thanks to its characteristics, CYGNO is expected to be sensitive to low mass dark matter (from 1 up to 10 GeV WIMP masses) with the potential to overcome the neutrino floor, that ultimately limits non-directional dark matter searches, pushing forward the frontiers of the knowledge in this area.

        Speaker: André Filipe Ventura Cortez (Istituto Nazionale di Fisica Nucleare)
    • 6:40 PM 6:50 PM
      Concluding remarks 10m
      Speaker: Konstantin Zioutas (University of Patras , PATRAS GREECE)