Leptophilic Dark Matter and AMS-02 Cosmic-ray Positron Flux

TL;DR

This paper investigates how leptophilic dark matter models can explain the high-energy positron flux observed by AMS-02, identifying dominant annihilation channels and their branching ratios.

Contribution

It provides a detailed analysis of dark matter annihilation channels that best fit AMS-02 positron data, including the impact of gauge boson final states.

Findings

Dark matter predominantly annihilates into ττ pairs.

Electron and muon channels are less than 20%.

Including gauge bosons reduces the required ττ branching ratio.

Abstract

With the measurement of positron flux published recently by AMS-02 collaboration, we show how the leptophilic dark matter fits the observation. We obtain the percentages of different products of dark matter annihilation that can best describe the flux of high energy positrons observed by AMS. We show that dark matter annihilates predominantly into $\tau\tau$ pair, while both $ee$ and $\mu\mu$ final states should be less than $20\%$. When gauge boson final states are included, the best branching ratio of needed $\tau\tau$ mode reduces.