Cosmic-Ray Positrons Strongly Constrain Leptophilic Dark Matter

Understand

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 Helium and proton measurements, we produce a robust fit to the local positron flux and spectrum.