Constraining Leptogenesis from Laboratory Experiments

Abstract

The presently available information on neutrino oscillations can be used to tightly constrain the light neutrino mass matrix $m_\n$ under the assumption that the three known neutrinos provide explanation of the solar and atmospheric anomalies. We exploit left right symmetry and the seesaw model to establish direct correlation between this constrained $m_\n$ and the mass matrix $M_R$ for the right handed (RH) neutrinos. Using this correlation, one could directly relate the lepton asymmetry $\e$ generated in the decay of the lightest RH neutrino to experimentally determined mixing angles of the light neutrinos. It is found that the parameters required to understand neutrino anomalies also give rise to the $\e$ in the range required to reproduce the correct baryon asymmetry in the leptogenesis scenario. Specifically, the small angle MSW or the the vacuum oscillation explanation of the solar anomaly can lead to correct $\e$ for maximal value of the CP violating phases. In contrast, the large angle MSW solution needs some suppression in CP violating phases in order to generate the right $\e$.