Enhanced cosmic-ray antihelium production from dark matter annihilation through light mediators

TL;DR

This paper proposes that dark matter annihilation via light mediators around 8 GeV can significantly boost cosmic-ray antihelium production, potentially making it detectable by current experiments despite previous constraints.

Contribution

It introduces a novel scenario where light mediators enhance antihelium production from dark matter annihilation, overcoming previous detection limitations.

Findings

Antihelium flux can be increased by three orders of magnitude.

Enhanced flux is within AMS-02 sensitivity.

Scenario consistent with existing antiproton and gamma-ray constraints.

Abstract

Cosmic-ray (CR) antihelium is an important probe for the indirect search of dark matter (DM) annihilation in the Galaxy. However, due to stringent constraints from the measurements of CR antiprotons and $\gamma$-rays, the flux of CR antihelium from the conventional DM direct annihilation into Standard Model final states is expected to be far below the sensitivity of the current experiments. We show that the production of antihelium can be significantly enhanced if the DM particles annihilate through light mediator particles with a mass $m_\phi \approx 8$ GeV close to the antihelium production threshold. After taking into account the constraints from the AMS-02 antiproton data and the Fermi-LAT $\gamma$-ray data on the spheroidal dwarf galaxies, we find that in this scenario the CR antihelium flux can be enhanced by three orders of magnitude, which makes it within the sensitivity of the ongoing AMS-02 experiment.