We propose a novel framework where light (sub-GeV) dark matter (DM) is detectable with future MeV γ-ray telescopes without conflicting with cosmic microwave background (CMB) data. The stable DM particle χ has a very low thermal relic abundance due to its large pair-annihilation cross section. The DM number density is stored in a slightly heavier, metastable partner ψ with suppressed pair-annihilation rates, that does not perturb the CMB, and whose late-time decays ψ→χ fill the Universe with χ DM particles. We provide explicit, model-independent realizations for this framework, and discuss constraints on late-time decays, and thus on parameters of this setup, from CMB, big bang nucleosynthesis, and large scale structure.
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http://dx.doi.org/10.1103/PhysRevLett.121.071101 | DOI Listing |
Phys Rev Lett
December 2024
Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Via Marzolo 8, 35131 Padova, Italy.
We revisit supernova (SN) bounds on a hidden sector consisting of millicharged particles χ and a massless dark photon. Unless the self-coupling is fine-tuned to be small, rather than exiting the SN core as a gas, the particles form a relativistic fluid and subsequent dark QED fireball, streaming out against the drag due to the interaction with matter. Novel bounds due to excessive energy deposition in the mantle of low-energy supernovae can be obtained.
View Article and Find Full Text PDFCommun Phys
December 2024
C. N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, NY 11794 USA.
Solid-state detectors with a low energy threshold have several applications, including searches of non-relativistic halo dark-matter particles with sub-GeV masses. When searching for relativistic, beyond-the-Standard-Model particles with enhanced cross sections for small energy transfers, a small detector with a low energy threshold may have better sensitivity than a larger detector with a higher energy threshold. In this paper, we calculate the low-energy ionization spectrum from high-velocity particles scattering in a dielectric material.
View Article and Find Full Text PDFComput Softw Big Sci
May 2024
Institut für Hochenergiephysik, Österreichischen Akademie der Wissenschaften, Nikolsdorfer Gasse 18, 1050 Wien, Austria.
Cryogenic phonon detectors with transition-edge sensors achieve the best sensitivity to sub-GeV/c dark matter interactions with nuclei in current direct detection experiments. In such devices, the temperature of the thermometer and the bias current in its readout circuit need careful optimization to achieve optimal detector performance. This task is not trivial and is typically done manually by an expert.
View Article and Find Full Text PDFPhys Rev Lett
May 2024
Theoretical Physics Division, Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA.
Detection of axion dark matter heavier than an meV is hindered by its small wavelength, which limits the useful volume of traditional experiments. This problem can be avoided by directly detecting in-medium excitations, whose ∼meV-eV energies are decoupled from the detector size. We show that for any target inside a magnetic field, the absorption rate of electromagnetically coupled axions into in-medium excitations is determined by the dielectric function.
View Article and Find Full Text PDFPhys Rev Lett
April 2024
College of Physics, Sichuan University, Chengdu 610065.
Recently a dark matter-electron (DM-electron) paradigm has drawn much attention. Models beyond the standard halo model describing DM accelerated by high energy celestial bodies are under intense examination as well. In this Letter, a velocity components analysis (VCA) method dedicated to swift analysis of accelerated DM-electron interactions via semiconductor detectors is proposed and the first HPGe detector-based accelerated DM-electron analysis is realized.
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