Baryogenesis: The Lepton Leaking Mechanism

We propose a baryo- and leptogenesis mechanism in which the B-L asymmetry is produced in the conversion of ordinary leptons into particles of some depleted hidden sector. In particular, we consider the lepton number violating reactions, l Higgs -> l' Higgs', \bar{l'} \bar{Higgs'}, mediated by the heavy Majorana neutrinos N of the seesaw mechanism, where l and Higgs are ordinary lepton and Higgs doublets and l', Higgs' the ``sterile'' leptons and Higgs. This mechanism can operate even if the reheat temperature is smaller than the N Majorana masses, in which case the usual leptogenesis mechanism through N decays is ineffective. In particular, the reheat tempearture can be as low as 10^9 GeV or less.