Testing The Light Dark Matter Hypothesis With AMS

TL;DR

This paper discusses how AMS could detect a distinctive positron bump around 7-10 GeV, which would support the hypothesis that dark matter particles cause certain gamma-ray and radio signals from the Galactic Center.

Contribution

It proposes that AMS can identify a specific positron feature indicative of dark matter annihilation, providing a new test for dark matter models explaining Galactic Center signals.

Findings

AMS can potentially detect a 7-10 GeV positron bump.

Detection of the bump would support dark matter origin of gamma-ray and radio signals.

No known astrophysical sources are expected to produce such a sharp positron feature.

Abstract

The spectrum and morphology of gamma-rays from the Galactic Center and the spectrum of synchrotron emission observed from the Milky Way's radio filaments have each been interpreted as possible signals of $\sim$7-10 GeV dark matter particles annihilating in the Inner Galaxy. In dark matter models capable of producing these signals, the annihilations should also generate significant fluxes of $\sim$7-10 GeV positrons which can lead to a distinctive bump-like feature in local cosmic ray positron spectrum. In this letter, we show that while such a feature would be difficult to detect with PAMELA, it would likely be identifiable by the currently operating AMS experiment. As no known astrophysical sources or mechanisms are likely to produce such a sharp feature, the observation of a positron bump at around 7-10 GeV would significantly strengthen the case for a dark matter interpretation of the reported gamma-ray and radio anomalies.