Derivation of very tiny masses of neutrinos in the left-right symmetric gauge model

Abstract

Very tiny mass values of neutrinos are derived in the left-right symmetric gauge model with spontaneous parity violation. In our scheme the Dirac mass terms of neutrinos vanish in the tree level, but they are induced in higher order and proportional to the charged-lepton mass terms. The relation, m ν l ⋍ G 0m l 2 m WR , with G 0⪅10 −13 for the three generations, is derived. We also discuss the model where the mixings among the lepton generations vanish.