An Interpretation of the Cosmic Ray $e^+\, +\, e^-$ Spectrum from 10 GeV to 3 TeV Measured by CALET on the ISS

A combined interpretation of the CALET $e^+\, +\, e^-$ spectrum up to 3 TeV and the AMS-02 positron spectrum up to 500 GeV was performed and the results are discussed. To parametrize the background electron flux, we assume a smoothly broken power-law spectrum with an exponential cut-off for electrons and fit this parametrization to the measurements, with either a pulsar or 3-body decay of fermionic Dark Matter as the extra electron-positron pair source responsible for the positron excess. We found that depending on the parameters for the background, both Dark Matter decay and the pulsar model can explain the combined measurements. While the Dark Matter decay scenario is constrained by the Fermi-LAT $\gamma$-ray measurement, we show that 3-body decay of a 800 GeV Dark Matter can be compatible with the $\gamma$-ray flux measurement. We discuss the capability of CALET to discern decaying Dark Matter models from a generic pulsar source scenario, based on simulated data for five years of data-taking.

PDF Abstract