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

Abstract

In SU(3) L × 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 ( ν) pair, is naturally included. The mechanism is shown to work in models with a heavy charged lepton, ω +, in a lepton triplet ( ν, ℓ, ω +) and with a heavy neutral lepton, N, in ( ν, ℓ, N). A minimal model with ℓ and ℓ c in ( ν, ℓ, ℓ c ) together with a sextet Higgs scalar suffers from a fine-tuning problem to suppress tree-level neutrino masses.