Annihilation of Secluded Dark Matter into W+W- Enhanced by P-wave Sommerfeld Effect

We propose that a pair of annihilation of the secluded dark matter may accommodate a source of the halo gamma ray signal reported recently, through the p-wave Sommerfeld enhancement. We show that given a weakly coupling of the dark sector to the Higgs bosons, the dark matter annihilation into W+W-, even though induced at 1-loop level, is desirably amplified. We also argue that the supersymmetric framework may readily embody such a model within rather minimal contents.