10 GeV dark matter candidates and cosmic-ray antiprotons

TL;DR

This paper examines 10 GeV dark matter candidates suggested by direct detection experiments and shows that their annihilation could produce antiprotons in cosmic rays, which current data may already constrain.

Contribution

It highlights the potential conflict between low-mass dark matter particle models and cosmic-ray antiproton measurements, emphasizing the importance of considering cosmic-ray data in dark matter studies.

Findings

Thermal annihilation cross section for 10 GeV dark matter likely exceeds antiproton flux limits.

Cosmic-ray antiproton data can constrain light dark matter models.

Light dark matter with quark couplings may be in tension with current cosmic-ray observations.

Abstract

Recent measurements performed with some direct dark matter detection experiments, e.g. CDMS-II and CoGENT (after DAMA/LIBRA), have unveiled a few events compatible with weakly interacting massive particles. The preferred mass range is around 10 GeV, with a quite large spin-independent cross section of $10^{-43}$-$10^{-41}\,{\rm cm^2}$. In this paper, we recall that a light dark matter particle with dominant couplings to quarks should also generate cosmic-ray antiprotons. Taking advantage of recent works constraining the Galactic dark matter mass profile on the one hand and on cosmic-ray propagation on the other hand, we point out that considering a thermal annihilation cross section for such low mass candidates very likely results in an antiproton flux in tension with the current data, which should be taken into account in subsequent studies.