Gauged B-3L_τ and baryogenesis

Abstract

It has recently been shown that by extending the minimal standard model to include a right-handed partner to ν_τ, it is possible to gauge the B-3L_τ quantum number consistently. If we add two scalar triplets, one trivial (ξ₁) and one nontrivial (ξ₂) under B-3L_τ, 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 ξ₁ into the lighter ξ₂ plus a neutral singlet (ζ⁰). This lepton asymmetry then gets converted into a baryon asymmetry at the electroweak phase transition.