Dark matter constraints from box-shaped gamma-ray features

TL;DR

This paper investigates box-shaped gamma-ray spectral features from dark matter interactions, deriving constraints from Fermi-LAT data that are competitive with traditional methods and applicable across various dark matter models.

Contribution

It introduces the use of box-shaped gamma-ray spectra as a novel signature for dark matter detection and provides the first comprehensive constraints using this feature with Fermi-LAT data.

Findings

Constraints are competitive with standard spectral feature methods.

Robust limits are obtained even for non-degenerate dark matter and intermediate masses.

Box-shaped spectra effectively constrain dark matter models.

Abstract

The observation of a sharp spectral feature in the gamma-ray sky would be one of the cleanest ways to identify dark matter and pinpoint its properties. Over the years a lot of attention has been paid to two specific features, namely gamma-ray lines and internal bremsstrahlung. Here, we explore a third class of spectral signatures, box-shaped gamma-ray spectra, that naturally arise in dark matter cascade annihilations or decays into intermediate particles that in turn decay into photons. Using Fermi-LAT data, we derive constraints on the dark matter parameter space for both annihilating and decaying dark matter, and show explicitly that our limits are competitive to strategies employing standard spectral features. More importantly, we find robust limits even in the case of non-degenerate dark matter and intermediate particle masses. This result is particularly relevant in constraining dark matter frameworks with gamma-ray data. We conclude by illustrating the power of box-shaped gamma-ray constraints on concrete particle physics scenarios.