Leptogenesis from additional Higgs doublets

Leptogenesis may be induced by the mixing of extra Higgs doublets with experimentally accessible masses. This mechanism relies on diagrammatic cuts that are kinematically forbidden in the vacuum but contribute at finite temperature. A resonant enhancement of the asymmetry occurs generically provided the dimensionless Yukawa and self-interactions are suppressed compared to those of the standard model Higgs field. This is in contrast to typical scenarios of resonant leptogenesis, where the asymmetry is enhanced by imposing a degeneracy of singlet neutrino masses.