Radiatively generated neutrino masses in SU(3)L X U(1)N gauge models

In SU(3)(L) x U(1)(N) gauge models for electroweak interactions, we discuss how to implement a radiative mechanism of generating Majorana neutrino masses by considering the property that the Higgs scalar, which has a coupling to a charged lepton (l)-neutrino (v) pair, is naturally included. The mechanism is shown to work in models with a heavy charged lepton, omega(+), in a lepton triplet(v, l, omega(+)) and with a heavy neutral lepton, N, in (v, l, N). A minimal model with l and l(c) in (v, l, l(c)) together with a sextet Higgs scalar suffers from a fine-tuning problem to suppress tree-level neutrino masses. (C) 1999 Published by Elsevier Science B.V. All rights reserved.