Cosmic-Ray Signatures of Dark Matter Decay

TL;DR

This paper explores how unstable dark matter decay could explain recent cosmic-ray anomalies, analyzing decay modes, observational constraints, and potential tests via gamma-ray anisotropies.

Contribution

It identifies specific dark matter decay modes that could account for positron and electron excesses and discusses observational constraints and future tests.

Findings

Decay modes compatible with observed anomalies

Constraints from antiproton and gamma-ray measurements

Potential for anisotropy measurements to test scenarios

Abstract

In light of recent observations of an anomalous excess of high-energy positrons and electrons by the PAMELA and Fermi LAT experiments, we investigate exotic cosmic-ray signatures in scenarios with unstable dark matter that decays with an extremely long lifetime. We identify decay modes capable of explaining the observed anomalies and mention constraints arising from measurements of antiprotons and gamma rays. We also discuss complementary tests by measurements of anisotropies in diffuse gamma rays which should be accessible to Fermi.