Heavy neutrino mass hierarchy from leptogenesis in left–right symmetric models with spontaneous CP-violation

Abstract

We consider left–right symmetric model with spontaneous CP-violation. The Lagrangian of this model is CP invariant and the Yukawa couplings are real. Due to spontaneous breaking of the gauge symmetry, some of the neutral Higgses acquire complex vacuum expectation values, which lead to CP-violation. In the model considered here, we identify the neutrino Dirac mass matrix with that of Fritzsch type charged lepton mass matrix. We assume a hierarchical spectrum of the right-handed neutrino masses and derive a bound on this hierarchy by assuming that the decay of the lightest right-handed neutrino produces the baryon asymmetry via the leptogenesis route. It is shown that the mass hierarchy we obtain is compatible with the current neutrino oscillation data.