Publications

Order by: publication date number of citations

• Dark matter or millisecond pulsars? A deep learning-based analysis of the Fermi Galactic Centre Excess

  Florian List, Nicholas L. Rodd, Geraint F. Lewis

  SciPost Phys. Proc. 12, 034 (2023) · published 4 July 2023 | Toggle abstract · pdf

  The $\gamma$-ray Galactic Centre Excess (GCE) remains one of the few observed high-energy signals for which a dark matter (DM) origin is a plausible explanation. We present a deep learning-based analysis of the $\gamma$-ray sky in the Galactic Centre region, carefully accounting for the mathematical degeneracy between faint point-sources (PSs) such as millisecond pulsars (MSPs) and DM-like Poisson emission. Using recent models for the Galactic foregrounds, we find that relatively few bright PSs just below Fermi's detection threshold seem unlikely to explain the GCE, although we continue to find evidence for PSs. Looking ahead, further improvements in the modelling of the $\gamma$-ray sky will be crucial for distinguishing between a DM-like and point-like morphology of the signal.

• remoTES: A new design for the cryogenic NaI detectors of the COSINUS experiment

  L. Einfalt, G. Angloher, Mukund Raghunath Bharadwaj, I. Dafinei, N. Di Marco, F. Ferroni, S. Fichtinger, A. Filipponi, T. Frank, M. Friedl, A. Fuss, Z. Ge, M. Heikinheimo, K. Huitu, M. Kellermann, R. Maji , M. Mancuso, L. Pagnanini, F. Petricca, S. Pirro, F. Pröbst, G. Profeta, A. Puiu, F. Reindl, K. Schäffner, J. Schieck, D. Schmiedmayer, C. Schwertner, M. Stahlberg, A. Stendahl, M. Stukel , F. Wagner, S. Yue, V. Zema, Y. Zhu

  SciPost Phys. Proc. 12, 033 (2023) · published 4 July 2023 | Toggle abstract · pdf

  The increasing statistical significance of the DAMA/LIBRA annual modulation signal is a cause for tension in the field of dark matter direct detection. The COSINUS experiment aims at a model-independent cross-check of the DAMA/LIBRA signal claim, using NaI crystals operated as cryogenic scintillating calorimeters at millikelvin temperatures. Such a setup enables measurement of phonon and scintillation light signals via Transition Edge Sensors (TESs) and allows particle discrimination on an event-by-event basis. The non-standard properties of NaI cause an obstacle when attaching a TES directly onto the surface of the crystal. This can be overcome with the ``remoTES'' design, where the TES is attached to an external wafer crystal. We present the results from a first successful operation of NaI and other crystals as cryogenic calorimeters with the remoTES design.

• Characterisation of low background CaWO$_4$ crystals for CRESST-III

  A. Kinast, G. Angloher, S. Banik, G. Benato, A. Bento, A. Bertolini, R. Breier, C. Bucci, J. Burkhart, L. Canonica, A. D'Addabbo, S. Di Lorenzo, L. Einfalt, A. Erb, F. v. Feilitzsch, N. Ferreiro Iachellini, S. Fichtinger, D. Fuchs, A. Fuss, A. Garai, V.M. Ghete, S. Gerster, P. Gorla, P.V. Guillaumon, S. Gupta, D. Hauff, M. Ješkovský, J. Jochum, M. Kaznacheeva, H. Kluck, H. Kraus, A. Langenkämper, M. Mancuso, L. Marini, L. Meyer, V. Mokina, A. Nilima, M. Olmi, T. Ortmann, C. Pagliarone, L. Pattavina, F. Petricca, W. Potzel, P. Povinec, F. Pröbst, F. Pucci, F. Reindl, J. Rothe, K. Schäffner, J. Schieck, D. Schmiedmayer, S. Schönert, C. Schwertner, M. Stahlberg, L. Stodolsky, C. Strandhagen, R. Strauss, I. Usherov, F. Wagner, M. Willers, V. Zema (CRESST Collaboration)

  SciPost Phys. Proc. 12, 031 (2023) · published 4 July 2023 | Toggle abstract · pdf

  The CRESST-III experiment aims at the direct detection of dark matter particles via their elastic scattering off nuclei in a scintillating CaWO$_4$ target crystal. For many years CaWO$_4$ crystals have successfully been produced in-house at Technische Universität München with a focus on high radiopurity. To further improve the CaWO$_4$ crystals, an extensive chemical purification of the raw materials has been performed and the crystal TUM93 was produced from this powder. We present results from an $\alpha$-decay rate analysis performed on 344 days of data collected in the ongoing CRESST-III data-taking campaign. The $\alpha$-decay rate could significantly be reduced.

• Quenching Factor estimation of Na recoils in NaI(Tl) crystals using a low-energy pulsed neutron beam measurement

  Mukund Raghunath Bharadwaj, G. Angloher, P. S. Barbeau, I. Dafinei, N. Di Marco, L. Einfalt, F. Ferroni, S. Fichtinger, A. Filipponi , T. Frank , M. Friedl , A. Fuss, Z. Ge , S. Hedges, M. Heikinheimo, K. Huitu, M. Kellermann, R. Maji, M. Mancuso, L. Pagnanini, F. Petricca, S. Pirro, F. Pröbst , G. Profeta, A. Puiu, F. Reindl , K. Schäffner, J. Schieck, D. Schmiedmayer , C. Schwertner , M. Stahlberg , A. Stendahl, M. Stukel , F. Wagner, S. Yue, V. Zema, Y. Zhu

  SciPost Phys. Proc. 12, 028 (2023) · published 4 July 2023 | Toggle abstract · pdf

  NaI(Tl) based scintillation detectors have become a staple in the field of direct dark matter searches, with the DAMA-LIBRA experiment being the standout for its reported observation of an annually modulating WIMP-like signal which is in direct contrast with other results. In order to accurately calibrate the energies of WIMP-induced nuclear recoil signals, precise measurements of the quenching factor of the NaI crystals are essential for each of these experiments, as it is well established that electron recoils and nuclear recoils have dissimilar scintillation light yields. In this contribution, we present first preliminary results of an ongoing systematic study that has been carried out by the COSINUS collaboration and Duke University to measure the quenching factor of Na recoils. Five ultra-pure NaI crystals, manufactured by the Shanghai Institute for Ceramics, each of which have varying Tl dopant concentrations, were irradiated with a mono-energetic neutron beam at the Triangle Universities National Laboratory, North Carolina, USA to extract the quenching factor values in the low recoil energies of 1-30keV$_{nr}$.

  4 citations

• Dark Matter: DAMA/LIBRA and its perspectives

  R. Bernabei, P. Belli, F. Cappella, V. Caracciolo, R. Cerulli, C.J. Dai, A. d'Angelo, A. Incicchitti, A. Leoncini, X.H. Ma, V. Merlo, F. Montecchia, X.D. Sheng, Z.P. Ye

  SciPost Phys. Proc. 12, 025 (2023) · published 3 July 2023 | Toggle abstract · pdf

  The long-standing model-independent annual modulation effect measured by DAMA deep underground at Gran Sasso Laboratory with different experimental configurations is summarized and perspectives will be highlighted. DAMA/LIBRA-phase2 set-up, $\simeq$ 250 kg highly radio-pure NaI(Tl) confirms the evidence of a signal that meets all the requirements of the model independent Dark Matter annual modulation signature at high C.L.; the full exposure is 2.86 ton $\times$ yr over 22 annual cycles. The experiment is currently collecting data in the DAMA/LIBRA-phase2 empowered configuration with an even lower software energy threshold. Other recent claims are shortly commented.

  2 citations

• Status and future prospects of the NEWS-G experiment

  P. Knights on behalf of the NEWS-G Collaboration

  SciPost Phys. Proc. 12, 024 (2023) · published 3 July 2023 | Toggle abstract · pdf

  The NEWS-G collaboration is searching for light dark matter using spherical proportional counters. Access to the mass range from 50 MeV to 10 GeV is enabled by the combination of low energy threshold, light gaseous targets (H, He, Ne), and highly radio-pure detector construction. Several of the recent developments that have paved the way for the operation of a new 140 cm in diameter, spherical proportional counter are presented. Constructed and commissioned at LSM using 4N copper with a 500$\mu$xm electroplated inner layer, the detector is now installed in SNOLAB, where it has begun data taking. Building on the electroplating of the current detector, the collaboration construct its next detector directly in the underground laboratory, using ultra-pure copper electroforming. The design and construction of ECUME, a 140 cm in diameter spherical proportional counter fully electroformed underground is discussed, along with the potential to achieve sensitivity reaching the neutrino floor in light Dark Matter searches with a next-generation detector.

• The Scintillating Bubble Chamber Experiment

  Ben Broerman

  SciPost Phys. Proc. 12, 023 (2023) · published 3 July 2023 | Toggle abstract · pdf

  The Scintillating Bubble Chamber (SBC) collaboration is combining the well-established liquid argon and bubble chamber technologies to search for low-mass, GeV-scale dark matter. Liquid-noble bubble chambers benefit from the excellent electron-recoil insensitivity inherent in bubble chambers with the addition of energy reconstruction provided from the scintillation signal for background rejection. The projected sensitivity with a quasi-background-free 10-kg-year exposure at a 100 eV nuclear recoil threshold is approximately 10$^{-43}$ cm$^2$ for a 1 GeV/c$^2$ dark matter mass.

• Search for low mass WIMP dark matter with DarkSide-50

  Masato Kimura on behalf of DarkSide-50 Collaboration

  SciPost Phys. Proc. 12, 022 (2023) · published 3 July 2023 | Toggle abstract · pdf

  DarkSide-50 is a direct dark matter detection experiment at Laboratori Nazionali del Gran Sasso that uses argon as the target material. Exploiting the ionization signal from a dual-phase time projection chamber filled with low-radioactivity argon, it has set the most stringent exclusion limit on WIMPs with a mass of few $\mathrm{GeV}/c^2$. A new analysis has recently been carried out with a larger exposure, profiting from an improved understanding of the detector response and background model. An improvement of about a factor 10 in sensitivity is expected for a WIMP mass of 2 GeV/c$^2$.

  1 citation

• Dark matter directionality approach using ZnWO$_4$ crystal scintillators

  Vincenzo Caracciolo, Volodymyr Yakovych Degoda, Pierluigi Belli, Rita Bernabei, Y. A. Borovlev, Fabio Cappella, Riccardo Cerulli, Fedor A. Danevich, Antonella Incicchitti, Alice Leoncini, Vittorio Merlo, N. Cherubini, Dmytro V. Kasperovych, Y. P. Kogut, G. P. Podust, Oksana G. Polischuk, A. G. Postupaeva, V. N. Shlegel, Volodymyr I. Tretyak

  SciPost Phys. Proc. 12, 021 (2023) · published 3 July 2023 | Toggle abstract · pdf

  The development of low-background anisotropic detectors can offer a unique way to study those Dark Matter (DM) candidate particles able to induce nuclear recoils through the directionality technique. Among the anisotropic scintillators, the ZnWO$_{4}$ has unique features and is an excellent candidate for the purposes. Both the light output and the scintillation pulse shape depend on the impinging direction of heavy particles with respect to the crystallographic axes and can supply two independent modes to study the directionality and discriminate $\gamma/\beta$ radiation. Measurements to study the anisotropic and scintillation performances of ZnWO$_4$ are reported.

• Anisotropic ionization threshold and directional sensitivity in solid state DM detectors

  Matti Heikinheimo, Sebastian Sassi, Kimmo Tuominen, Kai Nordlund, Nader Mirabolfathi

  SciPost Phys. Proc. 12, 020 (2023) · published 3 July 2023 | Toggle abstract · pdf

  The threshold displacement energy for nuclear recoils depends strongly on the direction of the recoiling nucleus with respect to the crystal lattice. Assuming that similar dependence holds for the ionization threshold for low energy nuclear recoils, we explore the consequences of the resulting directional dependence of the observable event rate in ionization detectors. For low mass dark matter, this effect leads to a daily modulation in the event rate. We discuss how this effect can be utilized to separate the DM signal from the solar neutrino background and how the structure of the modulation signal can be used to identify the type of the DM-nucleon coupling.