R-violating decay of Wino dark matter and electron/positron excesses in the PAMELA/Fermi experiments

We show that R-parity violating decay of Wino dark matter of mass about 3 TeV can naturally account for the flux and spectral shape of the cosmic-ray electrons and positrons observed by the PAMELA and Fermi satellites. To provide a theoretical basis for the scenario, we present a model in which trilinear R-parity breaking appears with a coefficient suppressed by powers of the gravitino mass, which naturally leads to the Wino lifetime of O(1026) seconds.