Dynamical Dark Matter and the Positron Excess in Light of AMS

Understand

The AMS-02 experiment has recently released data which confirms a rise in the cosmic-ray positron fraction as a function of energy up to approximately 350 GeV.

• Over the past decade, attempts to interpret this positron excess in terms of dark-matter decays have become increasingly complex and have led to a number of general expectations about the decaying dark-matter particles: such particles cannot undergo simple two-body decays to leptons, for example, and they must have rather heavy TeV-scale masses.
• In this paper, by contrast, we show that Dynamical Dark Matter (DDM) can not only match existing AMS-02 data on the positron excess, but also accomplish this feat with significantly lighter dark-matter constituents undergoing simple two-body decays to leptons.
• Moreover, we demonstrate that this can be done without running afoul of numerous other competing constraints from FERMI and Planck on decaying dark matter.