Interpretation of the cosmic ray positron and electron excesses with an annihilating-decaying dark matter scenario

Abstract

The precise measurements of energy spectra of cosmic ray positrons and/or electrons by recent experiments show clear excesses above 10 GeV. Moreover, a potential sharp spectral feature was suggested by the Dark Matter Particle Explorer (DAMPE) data. These results inspire quite a number of discussions on the connection with either the annihilation/decay of dark matter (DM) or the astrophysical origins. Here we discuss a DM scenario in which DM particles could annihilate and decay into standard model particle pairs simultaneously. In this model, the peak structure is due to the DM annihilation in a nearby subhalo and the broad positron/electron excesses are due to the decay of DM in the Milky Way. This model can reasonably explain the DAMPE and AMS-02 data of the total $e^+e^-$ spectra and the positron fraction, with model parameters being consistent with existing constraints. A simple realization of such a DM model is the spin-1 vector DM model.