WIMPy Leptogenesis With Absorptive Final State Interactions

Understand

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.