Prospects of antideuteron detection from dark matter annihilations or decays at AMS-02 and GAPS

TL;DR

This paper assesses the potential for detecting dark matter signals via cosmic antideuterons at AMS-02 and GAPS, considering constraints from antiproton measurements and modeling antideuteron formation and flux.

Contribution

It provides a detailed coalescence model analysis and calculates upper limits on antideuteron detection from dark matter, highlighting detection challenges.

Findings

Antideuteron detection from dark matter is highly constrained by existing antiproton data.

The coalescence momentum depends on the process and energy, affecting flux predictions.

Detection at AMS-02 and GAPS is challenging due to low expected fluxes.

Abstract

The search for cosmic antideuterons has been proposed as a promising method to indirectly detect dark matter, due to the very small background flux from spallations expected at the energies relevant to experiments. The antideuteron flux from dark matter annihilations or decays is, however, severely constrained by the non-observation of an excess in the antiproton-to-proton fraction measured by PAMELA. In this paper we calculate, for representative dark matter annihilation and decay channels, upper limits on the number of antideuteron events at AMS-02 and GAPS from requiring that the associated antiproton flux is in agreement with the PAMELA data. To this end, we first analyze in detail the formation of antideuterons in the coalescence model using an event-by-event Monte Carlo simulation and using data from various high energy experiments. We find that the resulting coalescence momentum shows a dependence on the underlying process and on the center of mass energy involved. Then, we calculate, using a diffusion model, the flux of antideuterons at the Earth from dark matter annihilations or decays. Our results indicate that, despite the various sources of uncertainty, the observation of an antideuteron flux at AMS-02 or GAPS from dark matter annihilations or decays will be challenging.