Quark lepton mass hierarchies and the baryon asymmetry

The mass hierarchies of quarks and charged leptons as well as a large νμ–ντ mixing angle are naturally explained by the Frogatt-Nielsen mechanism with a nonparallel family structure of chiral charges. We extend this mechanism to right-handed neutrinos. Their out-of-equilibrium decay generates a cosmological baryon asymmetry whose size is quantized in powers of the hierarchy parameter ϵ2. For the simplest hierarchy pattern the neutrino mass m̄ν=(mνμmντ)1/2∼10−2 eV, which is inferred from present indications for neutrino oscillations, implies a baryon asymmetry nB/s∼10−10. The corresponding baryogenesis temperature is TB∼1010 GeV.