Novel Spectral Features in MeV Gamma Rays from Dark Matter

TL;DR

This paper proposes a new spectral feature in MeV gamma rays from dark matter interactions, which could serve as a distinctive signature in upcoming astrophysical experiments, aiding in dark matter detection.

Contribution

Introduction of a novel class of spectral features in MeV gamma rays associated with near-threshold meson production in dark matter processes.

Findings

Spectral features are detectable with upcoming experiments like e-ASTROGAM and ComPair.

These features can serve as a clear signature for dark matter detection.

Forecasts show promising sensitivity for identifying these signals.

Abstract

Astrophysical searches for gamma rays are one of the main strategies to probe the annihilation or decay of dark matter particles. We present a new class of distinct sub-GeV spectral features that generically appear in kinematical situations where the available center-of-mass energy in such processes is just above threshold to produce excited meson states. Using a Fisher forecast with realistic astrophysical backgrounds, we demonstrate that for upcoming experiments like e-ASTROGAM and ComPair these signals can turn out to be the smoking gun in the search for particle dark matter.