BEXCO - Room F(201/202/203/204)
[DM018] Searching for Cosmic-Ray Signals from Decay of Fermionic Dark Matter with CALET
The ISS-based CALET detector which is in operation since October 2015, can play an important role in indirect detection of Dark Matter by measuring the electron+positron cosmic-ray spectrum in the TeV region for the first time directly. With its fine energy resolution (≈ 2%) and high proton rejection ratio (1:〖10〗^5 ), CALET has the potential to search for fine structures in this spectrum. We have investigated CALET’s capability to discern between scenarios in which the cosmic-ray positron excess is caused by Dark Matter decay or annihilation, and those in which it is caused by nearby pulsars. We fit a parametrization of the local electron and positron spectra to current measurements, with either a 3-body decay of Fermionic Dark Matter or a pulsar as the extra source responsible for the positron excess. Expected CALET data for the Dark Matter decay scenarios which explain the positron excess are calculated and analysed. The signal from this particular 3-body Dark Matter decay which can explain the recent measurements from the AMS−02 experiment is shown to be distinguishable from a single pulsar source causing the positron excess by five years of observation with CALET, based on the shape of the spectrum. We show that an especially clear separation between these two models is possible for Dark Matter candidates, for which the γ−ray emission from the decay is sufficiently low to be possibly compatible with the Fermi-LAT diffuse γ−ray data.