Comment on the lepton mixing matrix

The problem of finding a suitable parametrization for a nontrivial lepton mixing matrix is considered in the framework of the "sequential" Weinberg-Salam theory. It is noted that in the case of n lepton generations there are in fact n+1 different theories, corresponding to different numbers m of right-handed neutrino fields present in the Lagrangian. These (n, m) models conserve CP for leptonic couplings naturally only for m=0 or 1 when n3. These models would seem to be useful as self-consistent approximations for reducing the number of parameters in the experimental analysis of lepton mixing matrices.