Gauged $B-3L_{\tau }$ and Baryogenesis

Abstract

It has recently been shown that by extending the minimal standard model to include a right-handed partner to ${\nu }_{\tau }$, it is possible to gauge the $B-3L_{\tau }$ quantum number consistently. If we add two scalar triplets, one trivial (${\xi }_1$) and one nontrivial (${\xi }_2$) under $B-3L_{\tau }$, it is possible also to have desirable neutrino masses and mixing for neutrino oscillations. At the same time, a lepton asymmetry can be generated in the early universe through the novel mechanism of the decay of the heavier ${\xi }_1$ into the lighter ${\xi }_2$ plus a neutral singlet (${\zeta }^0$). This lepton asymmetry then gets converted into a baryon asymmetry at the electroweak phase transition.

Comments: 16 pages including two postscript figures