WIMPy Leptogenesis
  We consider a class of leptogenesis models in which the lepton asymmetry
arises from dark matter annihilation processes which violate CP and lepton
number. Importantly, a necessary one-loop contribution to the annihilation
matrix element arises from absorptive final state interactions. We elucidate
the relationship between this one-loop contribution and the CP-violating phase.
As we show, the branching fraction for dark matter annihilation to leptons may
be small in these models, while still generating the necessary asymmetry.
