Novel dark matter constraints from antiprotons in the light of AMS-02

TL;DR

This paper uses AMS-02 cosmic-ray antiproton data to set new constraints on dark matter properties, revealing a potential signal near 80 GeV that aligns with gamma-ray excess interpretations, while strengthening limits elsewhere.

Contribution

It provides a comprehensive analysis of dark matter constraints from antiprotons, incorporating propagation uncertainties and revealing a possible dark matter signal around 80 GeV.

Findings

Potential dark matter signal at ~80 GeV with significance ~4.5 sigma.

Strong constraints excluding thermal annihilation below 50 GeV and between 150-500 GeV.

Limits surpass gamma-ray dwarf galaxy constraints by a factor of 4 in most ranges.

Abstract

We evaluate dark matter (DM) limits from cosmic-ray antiproton observations using the recent precise AMS-02 measurements. We properly take into account cosmic-ray propagation uncertainties fitting at the same time DM and propagation parameters, and marginalizing over the latter. We find a significant (~4.5 sigma) indication of a DM signal for DM masses near 80 GeV, with a hadronic annihilation cross-section close to the thermal value, sigma v ~3e-26 cm3s-1. Intriguingly, this signal is compatible with the DM interpretation of the Galactic center gamma-ray excess. Confirmation of the signal will require a more accurate study of the systematic uncertainties, i.e., the antiproton production cross-section, and modelling of the solar modulation effect. Interpreting the AMS-02 data in terms of upper limits on hadronic DM annihilation, we obtain strong constraints excluding a thermal annihilation cross-section for DM masses below about 50 GeV and in the range between approximately 150 and 500 GeV, even for conservative propagation scenarios. Except for the range around 80 GeV, our limits are a factor 4 stronger than the limits from gamma-ray observations of dwarf galaxies.