Thermal Effects of Standard-Model Leptons in the Early Universe
by
The low-scale type-I seesaw is a well-motivated framework in which sterile neutrinos generate the Standard-Model neutrino masses, can account for the matter-antimatter asymmetry and dark matter, and may be probed at colliders. Two mechanisms have long dominated low-scale leptogenesis: resonant leptogenesis (RL), where the asymmetry is enhanced by near-degenerate sterile-neutrino masses, and leptogenesis via sterile-neutrino oscillations (ARS). In this talk, I present a third mechanism, thermally induced resonant leptogenesis (TIRL), in which finite-temperature effects of the SM leptons become important. I will explain how TIRL works and how it differs from RL and ARS, including the mass degeneracy of sterile neutrinos and resonance from thermally resummed leptons.