Spectral cutoffs in indirect dark matter searches

TL;DR

This paper explores the potential of detecting sharp spectral features like cutoffs or bumps in gamma-ray spectra as signals of dark matter, using atmospheric Cherenkov telescopes, to distinguish dark matter signals from astrophysical backgrounds.

Contribution

It analyzes the prospects of identifying spectral features such as cutoffs or bumps in gamma-ray data as signatures of dark matter with current and future telescopes.

Findings

Spectral features can serve as clear dark matter signatures.

Atmospheric Cherenkov Telescopes have promising sensitivity for these features.

Detection prospects depend on dark matter models and telescope capabilities.

Abstract

Indirect searches for dark matter annihilation or decay products in the cosmic-ray spectrum are plagued by the question of how to disentangle a dark matter signal from the omnipresent astrophysical background. One of the practically background-free smoking-gun signatures for dark matter would be the observation of a sharp cutoff or a pronounced bump in the gamma-ray energy spectrum. Such features are generically produced in many dark matter models by internal Bremsstrahlung, and they can be treated in a similar manner as the traditionally looked-for gamma-ray lines. Here, we discuss prospects for seeing such features with present and future Atmospheric Cherenkov Telescopes.