CP VIOLATION IN THE LEPTON SECTOR WITH MAJORANA NEUTRINOS

We study CP violation in the lepton sector in extended models with rig ht-handed neutrinos, without and with left-right symmetry, and with ar bitrary mass terms. We find the conditions which must be satisfied by the neutrino and charged lepton mass matrices for CP conservation, The se constraints, which are independent of the choice of weak basis, are proven to be also sufficient in simple cases, This invariant formulat ion makes apparent the necessary requirements for CP violation, as wel l as the size of CP violating effects. As an example, we show that CP violation can be much larger in left-right symmetric models than in mo dels with only additional right-handed neutrinos, i.e., without right- handed currents.