CP VIOLATION IN NEUTRINO MIXING MATRIX AND LEPTOGENESIS

Abstract

The CP violation required in leptogenesis may have different origin, but in an effective theory they are all related to the rephasing invariant CP violating measures in the mixing matrix of the leptonic sector. We point out that with our present knowledge of the mixing angles it is possible to estimate the maximum allowed value for all the rephasing invariant measures of CP violation in the leptonic sector. In the effective three-generation scenario there are three CP violating rephasing invariant measures. We show that only one rephasing invariant measure enters the lepton number conserving processes while the other two enter the lepton number violating processes. In the bimaximal mixing case, the lepton number conserving measure of CP violation vanishes while the two lepton number violating rephasing invariant measures of CP violation remain nonzero, which could contribute to the lepton asymmetry of the universe.