Minimal See-Saw Model for Atmospheric and Solar Neutrino Oscillations

Abstract

We present a minimal see-saw model based on an extension of the standard model (SM) which includes an additional U(1), with gauge charge $B-\frac{3}{2}(L_{\mu }+L_{\tau })$. Requirement of anomaly cancellation implies the existence of two right-handed singlet neutrinos, carrying this gauge charge, which have normal Dirac couplings to ${\nu }_{\mu }$ and ${\nu }_{\tau }$ but suppressed ones to ${\nu }_e$. Assuming the U(1) symmetry breaking scale to be 10${}^{12-16}$~GeV, this model can naturally account for the large (small) mixing solutions to the atmospheric (solar) neutrino oscillations.

Comments: 14 pages, latex, no figures