Quark Lepton Mass Hierarchies and the Baryon Asymmetry

Abstract

The mass hierarchies of quarks and charged leptons as well as a large ${\text{n}}_{\text{m}}$-${\text{n}}_{\text{t}}$ 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 ${\text{e}}^2$. For the simplest hierarchy pattern the neutrino mass ${\bar{m}}_{\text{n}}=(m_{{\text{n}}_{\text{m}}}{m}_{{\text{n}}_{\text{t}}}{)}^{1/2}\sim 10^{-2}$ eV, which is inferred from present indications for neutrino oscillations, implies a baryon asymmetry $n_B/s\sim 10^{-10}$. The corresponding baryogenesis temperature is $T_B\sim 10^{10}$ GeV.

Comments: 7 pages