Neutrino masses in left-right symmetric models

Radiative corrections to the Majorana neutrino mass in the left-right symmetric models are calculated in the presence of one or two SU(2)L doublets in the theory. In the former case, the radiative corrections are essential for large (a few hundred GeV) masses of the Higgs field. If the second SU(2)L doublet exists in the theory, then it makes an additional essential contribution to the neutrino mass, provided that the Dirac masses of charged leptons are much less than the Dirac masses of neutrino (me/mνD << 1). It the latter case, not only massses, but also mixing angles of neutrinos may considerably differ from the tree approximation