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. (C) 1998 Elsevier Science B.V. All rights reserved. [References: 22]
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