Sleptogenesis

Abstract

We propose that the observed baryon asymmetry of the Universe can naturally arise from a net asymmetry generated in the right-handed sneutrino sector at fairly low reheat temperatures. The initial asymmetry in the sneutrino sector is produced from the decay of the inflaton, and is subsequently transferred into the standard model (s)lepton doublet via three-body decay of the sneutrino. Our scenario relies on two main assumptions: a considerable branching ratio for the inflaton decay to the right-handed (s)neutrinos, and Majorana masses which are generated by the Higgs mechanism. The marked feature of this scenario is that the lepton asymmetry is decoupled from the neutrino Dirac Yukawa couplings. We exhibit that our scenario can be embedded within minimal models which seek the origin of a tiny mass for neutrinos.