Baryogenesis in the Singlet Majoron Model

Abstract

The baryogenesis by decays of the right--handed neutrinos in the Majoron model is studied. We show that compared to the observational value it is possible to produce large enough baryon asymmetry in the Majoron model or, at least, contribute strongly to it. It requires that the mass of the lightest right--handed neutrino is about (or above) 1 TeV and the self coupling of the singlet sector is weak enough, $ < 2\times 10^{-5}$, to prevent the thermalization of the right--handed neutrinos by annihilations.