Antideuterons from Dark Matter Decay

TL;DR

This paper explores how dark matter decay could produce detectable antideuterons in cosmic rays, potentially exceeding secondary production and aligning with recent positron excess observations, with implications for upcoming experiments.

Contribution

It demonstrates that dark matter decay can generate significant antideuteron fluxes, which may be observable by future cosmic-ray experiments, providing a new indirect detection channel.

Findings

Antideuteron flux from dark matter decay can surpass secondary flux.

Predicted fluxes could be within reach of AMS-02 and GAPS.

Dark matter decay may explain positron excess observed by PAMELA.

Abstract

Recent observations of a large excess of cosmic-ray positrons at high energies have raised a lot of interest in leptonic decay modes of dark matter particles. Nevertheless, dark matter particles in the Milky Way halo could also decay hadronically, producing not only a flux of antiprotons but also a flux of antideuterons. We show that for certain choices of parameters the antideuteron flux from dark matter decay can be much larger than the purely secondary flux from spallation of cosmic rays on the interstellar medium, while the total antiproton flux remains consistent with present observations. We show that if the dark matter particle is sufficiently light, the antideuteron flux from dark matter decay could even be within the reach of planned experiments such as AMS-02 or GAPS. Furthermore, we discuss the prospects to observe the antideuteron flux in the near future if the steep rise in the positron fraction reported by the PAMELA collaboration is interpreted in terms of the decay of dark matter particles.