Neutrino mass through concomitant breakdown of the U(1) chiral and scale symmetries

Abstract

The possibility of generating neutrino mass through see-saw mechanism involving U(1) chiral Peccei-Quinn and scale symmetries breakdown is discussed. We consider a generic scale invariant model which has three Majorana fermions and a complex scalar singlet, which might be the one responsible for an invisible axion, and we perform a summation of all leading-logarithmic radiative corrections to the tree level potential. The effective potential so obtained is stable and drives the scalar field to a nonzero vacuum expectation value according to the Coleman-Weinberg mechanism. As a result, right-handed neutrinos gain mass at the Peccei-Quinn scale which is suggestive for explaining very light active neutrinos. We illustrate the whole idea with the addition of the standard model, and also a $\mathrm{SU}(3{)}_L\otimes \mathrm{U}(1{)}_X$ model in which the subgroup $\mathrm{SU}(2{)}_L\otimes \mathrm{U}(1{)}_Y$ is constrained to be broken as an effect of the effective potential. This last model presents electric charge quantization as well.