Decaying dark matter in light of the PAMELA and Fermi LAT data

Abstract

A series of experiments measuring high-energy cosmic rays have recentlyreported strong indications for the existence of an excess of high-energyelectrons and positrons. If interpreted in terms of the decay of dark matterparticles, the PAMELA measurements of the positron fraction and the Fermi LATmeasurements of the total electron-plus-positron flux restrict the possibledecaying dark matter scenarios to a few cases. Analyzing different decaychannels in a model-independent manner, and adopting a conventional diffusivereacceleration model for the background fluxes of electrons and positrons, weidentify some promising scenarios of dark matter decay and calculate thepredictions for the diffuse extragalactic gamma-ray flux, including thecontributions from inverse Compton scattering with the interstellar radiationfield.