Resonant Annihilation of WIMP Dark Matter for Halo Gamma Ray Signal

We propose a resonant annihilation as a way to reconcile the WIMP annihilation cross sections in a recently reported gamma ray signal from the Milky Way halo with that for the freeze-out and the upper limit from dwarf galaxies. We perform a simple model-independent analysis based on this hypothesis and determine the required parameters. We also present a simple particle-physics model that can accommodate them.