  A series of experiments measuring high-energy cosmic rays have recently
reported strong indications for the existence of an excess of high-energy
electrons and positrons. If interpreted in terms of the decay of dark matter
particles, the PAMELA measurements of the positron fraction and the Fermi LAT
measurements of the total electron-plus-positron flux restrict the possible
decaying dark matter scenarios to a few cases. Analyzing different decay
channels in a model-independent manner, and adopting a conventional diffusive
reacceleration model for the background fluxes of electrons and positrons, we
identify some promising scenarios of dark matter decay and calculate the
predictions for the diffuse extragalactic gamma-ray flux, including the
contributions from inverse Compton scattering with the interstellar radiation
field.
