BARYOGENESIS VIA NEUTRINO OSCILLATIONS

We propose a new mechanism of leptogenesis in which the asymmetries in lepton numbers are produced through the CP-violating oscillations of ''sterile'' (electroweak singlet) neutrinos. The asymmetry is communic ated from singlet neutrinos to ordinary leptons through their Yukawa c ouplings. The lepton asymmetry is then reprocessed into baryon asymmet ry by electroweak sphalerons. We show that the observed value of baryo n asymmetry can be generated in this way, and the masses of ordinary n eutrinos induced by the seesaw mechanism are in the astrophysically an d cosmologically interesting range. Except for singlet neutrinos, no p hysics beyond the standard model is required.