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Dark matter (DM) annihilations have been widely studied as a possibleexplanation of excess gamma rays from the galactic center seen by Fermi/LAT.However most such models are in conflict with constraints from dwarfspheroidals. Motivated by this tension, we show that p-wave annihilating darkmatter can easily accommodate both sets of observations due to the lower DMvelocity dispersion in dwarf galaxies. Explaining the DM relic abundance isthen challenging. We outline a scenario in which the usual thermal abundance isobtained through s-wave annihilations of a metastable particle, that eventuallydecays into the p-wave annihilating DM of the present epoch. The couplings andlifetime of the decaying particle are constrained by big bang nucleosynthesis,the cosmic microwave background and direct detection, but significant regionsof parameter space are viable. A sufficiently large p-wave cross section can befound by annihilation into light mediators, that also give rise to Sommerfeldenhancement. A prediction of the scenario is enhanced annihilations in galaxyclusters.

p-wave Annihilating Dark Matter from a Decaying Predecessor and the Galactic Center Excess