Search

Light dark matter (DM), defined here as having a mass between 1 MeV and about 1 GeV, is an interesting possibility both theoretically and phenomenologically, at one of the frontiers of current progress in the field of DM searches. Its indirect detection via gamma rays is challenged by the scarcity of experiments in the MeV-GeV region. We look therefore at lower-energy x-ray data from the INTEGRAL telescope, and compare them with the predicted DM flux. We derive bounds which are competitive with existing ones from other techniques. Crucially, we include the contribution from inverse Compton scattering on galactic radiation fields and the cosmic microwave background, which leads to much stronger constraints than in previous studies for DM masses above 20 MeV. [ABSTRACT FROM AUTHOR]

The observation of cosmic sub-PeV gamma rays from the Crab Nebula opens up the possibility of testing cosmic ray photon transparency at the multi-hundred-TeV scale. Assuming no deviation from a source gamma-ray emission due to accelerated electron inverse-Compton scattering, higher event energies can extend constraints on the effects of new physics; we consider oscillation between gamma rays and axions, plus attenuation effects from gamma-ray absorption in the case of dark photon dark matter. Combining the recent ASγ and HAWC sub-PeV data with earlier MAGIC and HEGRA data, axionlike particles are most constrained in the 2×10-7-6×10-7 eV mass range, where the coupling gaγγ is constrained to be below 1.8×10-10 GeV-1. Direct scattering from dark photon dark matter limits kinetic mixing ε≲10-3 for masses between 0.01 and 1 eV. [ABSTRACT FROM AUTHOR]