Decaying Dark Matter in Supersymmetric Model and Cosmic-Ray Observations

Abstract: We study cosmic-rays in decaying dark matter scenario, assuming that the dark matter is the lightest superparticle and it decays through a R-parity violating operator. We calculate the fluxes of cosmic-rays from the decay of the dark matter and those from the standard astrophysical phenomena in the same propagation model using the GALPROP package. We reevaluate the preferred parameters characterizing standard astrophysical cosmic-ray sources with taking account of the effects of dark matter decay. We show that, if energetic leptons are produced by the decay of the dark matter, the fluxes of cosmic-ray positron and electron can be in good agreements with both PAMELA and Fermi-LAT data in wide parameter region. It is also discussed that, in the case where sizable number of hadrons are also produced by the decay of the dark matter, the mass of the dark matter is constrained to be less than 200-300 GeV in order to avoid the overproduction of anti-proton. We also show that the cosmic gamma-ray flux can be consistent with the results of Fermi-LAT observation if the mass of the dark matter is smaller than nearly 4 TeV.