Cosmic-ray positrons strongly constrain leptophilic dark matter. Issue 12 (3rd December 2021)

• Record Type: Journal Article
• Authors: John, Isabelle; Linden, Tim
• Is Part Of: Journal of cosmology and astroparticle physics. Volume 2021:Issue 12(2021)
• Publication Date: 2021-12-03
• Subjects: cosmic ray theory -- dark matter simulations -- dark matter theory; Cosmology -- Periodicals; Astrophysics -- Periodicals; 523.0105
• DOI: 10.1088/1475-7516/2021/12/007
• Languages: English
• ISSNs: 1475-7516

Abstract

Abstract: Cosmic-ray positrons have long been considered a powerful probe of dark matter annihilation. In particular, myriad studies of the unexpected rise in the positron fraction have debated its dark matter or pulsar origins. In this paper, we instead examine the potential for extremely precise positron measurements by AMS-02 to probe hard leptophilic dark matter candidates that do not have spectral features similar to the bulk of the observed positron excess. Utilizing a detailed cosmic-ray propagation model that includes a primary positron flux generated by Galactic pulsars in addition to a secondary component constrained by He and proton measurements, we produce a robust fit to the local positron flux and spectrum. We find no evidence for a spectral bump correlated with leptophilic dark matter, and set strong constraints on the dark matter annihilation cross-section that fall below the thermal annihilation cross-section for dark matter masses below 60 GeV and 380 GeV for annihilation into τ + τ - and e + e -, respectively, in our default model.