Connecting leptonic CP violation, lightest neutrino mass and baryon asymmetry through type II seesaw

Abstract

We study the possibility of connecting leptonic Dirac CP phase δ, lightest neutrino mass and baryon asymmetry of the universe within the framework of a model where both type I and type II seesaw mechanisms contribute to neutrino mass. Type I seesaw gives rise to Tri-Bimaximal (TBM) type neutrino mixing whereas type II seesaw acts as a correction in order to generate nonzero θ13. We derive the most general form of type II seesaw mass matrix which cannot only give rise to correct neutrino mixing angles but also can generate nontrivial value of δ. Considering both the cases where type II seesaw is subleading and is equally dominant compared to type I seesaw, we correlate the type II seesaw term with δ and lightest neutrino mass. We further constrain the Dirac CP phase δ and hence the type II seesaw mass matrix from the requirement of producing the observed baryon asymmetry through the mechanism of leptogenesis.