Indirect constraints on the dark matter interpretation of excess positrons seen by AMS-02

TL;DR

This paper demonstrates that the leptophilic dark matter annihilation channels previously proposed to explain AMS-02 positron excess are ruled out by observational data from dwarf galaxies and cool-core clusters, challenging the dark matter interpretation.

Contribution

It provides the first comprehensive indirect constraints on all leptophilic dark matter channels explaining the positron excess.

Findings

Leptophilic channels are incompatible with Fermi/LAT dwarf galaxy data.

Cool-core cluster observations further exclude the remaining viable channels.

Dark matter explanation for AMS-02 positron excess is strongly constrained.

Abstract

Recently, an excess of high energy positrons in our Galaxy has been observed by AMS-02. The spectrum obtained can be best fitted with the annihilation of $\sim$ TeV dark matter particles. However, recent analysis of Dwarf galaxies by Fermi/LAT observations highly constrains the TeV dark matter annihilation cross-section, and rules out the $b\bar{b}$ and all the leptophilic channels except $4-\mu$ channel. In this article, I show that the remaining possible $4-\mu$ channel is also ruled out by using the observational data from cool-core clusters. Therefore, all the leptophilic channels that can account for the excess positrons seen in AMS-02, HEAT, and PAMELA are ruled out.