Note on the dark matter explanation of the ARCADE excess and AMS data

TL;DR

This paper demonstrates that positron data from AMS effectively rules out the hypothesis that self-annihilating dark matter explains the ARCADE radio background excess, challenging previous leptonic annihilation models.

Contribution

It provides a combined analysis of AMS positron data and radio excess models, conclusively excluding dark matter explanations for the ARCADE excess.

Findings

AMS positron data constrains dark matter annihilation cross-sections

Leptonic dark matter channels are incompatible with observed positron flux

Dark matter explanation for the radio excess is ruled out

Abstract

In this paper we show that positron data from AMS seems to rule out the explanation of the ARCADE isotropic radio background excess in terms of self-annihilating dark matter. In earlier works it was found that leptonic annihilation channels of light dark matter provide a good fit to the excess due to synchrotron emission of the final state particles. However, limits on the self-annihilation cross-section derived from the positron data of AMS now severely constrain light self-annihilating dark matter and cross-sections below that of a thermal relic are already tested for leptonic annihilation channels. Combining these two results, we conclude that an explanation of the excess in the radio background in terms of self-annihilating dark matter is excluded.