High-energy Cosmic-Ray Positrons from Hidden-Gauge-Boson Dark Matter

TL;DR

This paper proposes a hidden U(1) gauge boson as dark matter that decays into standard-model particles, explaining the PAMELA positron excess while producing minimal antiprotons, aligning with observational data.

Contribution

It introduces a novel dark matter decay mechanism via kinetic mixing with a U(1)_{B-L} gauge boson, naturally explaining cosmic-ray positron excesses with suppressed antiproton production.

Findings

The model accounts for the steep rise in positron fraction observed by PAMELA.

It predicts minimal antiproton production consistent with observational constraints.

The scenario provides a viable dark matter candidate explaining cosmic-ray anomalies.

Abstract

We provide a scenario in which a hidden U(1) gauge boson constitutes dark matter of the Universe and decays into the standard-model particles through a kinetic mixing with an $U(1)_{B-L}$ gauge boson. Interestingly, our model can naturally account for the steep rise in the positron fraction recently reported by PAMELA. Moreover, we find that due to the charge assignment of $U(1)_{B-L}$, only a small amount of antiprotons are produced in the decay, which is also consistent with the PAMELA and other observational data.