Indirect Detection of Dark Matter Using MeV-Range Gamma-Ray Telescopes

TL;DR

Future MeV-range gamma-ray telescopes can significantly enhance the detection sensitivity for low-mass dark matter annihilation or decay signals, especially in the 1-100 MeV energy range.

Contribution

This paper evaluates the potential of upcoming gamma-ray telescopes to detect low-mass dark matter signals, highlighting their improved sensitivity over current instruments.

Findings

Planned detectors can improve sensitivity by up to a few orders of magnitude.

Dark matter with masses below 140 MeV (annihilation) or 280 MeV (decay) produces detectable gamma-ray signals.

Final states mainly involve photons or neutral pions, providing distinctive signals.

Abstract

The astrophysics community is considering plans for a variety of gamma-ray telescopes (including ACT and GRIPS) in the energy range 1--100 MeV, which can fill in the so-called "MeV gap" in current sensitivity. We investigate the utility of such detectors for the study of low-mass dark matter annihilation or decay. For annihilating (decaying) dark matter with a mass below about 140 MeV (280 MeV) and couplings to first generation quarks, the final states will be dominated by photons or neutral pions, producing striking signals in gamma-ray telescopes. We determine the sensitivity of future detectors to the kinematically allowed final states. In particular, we find that planned detectors can improve on current sensitivity to this class of models by up to a few orders of magnitude.