Radiative Corrections to Neutrino Mixing and CP Violation in the Minimal Seesaw Model with Leptogenesis

Radiative corrections to neutrino mixing and CP violation are analyzed in the minimal seesaw model with two heavy right-handed neutrinos. We find that textures of the effective Majorana neutrino mass matrix are essentially stable against renormalization effects. Taking account of the Frampton-Glashow-Yanagida ansatz for the Dirac neutrino Yukawa coupling matrix, we calculate the running effects of light neutrino masses, lepton flavor mixing angles and CP-violating phases for both $m_1 =0$ (normal mass hierarchy) and $m_3 =0$ (inverted mass hierarchy) cases in the standard model and in its minimal supersymmetric extension. Very instructive predictions for the cosmological baryon number asymmetry via thermal leptogenesis are also given with the help of low-energy neutrino mixing quantities.Comment: 21 pages, 6 figures; more references adde

Renormalization Group Running of Lepton Mixing Parameters in See-Saw Models with S4S_4 Flavor Symmetry

We study the renormalization group running of the tri-bimaximal mixing predicted by the two typical $S_4$ flavor models at leading order. Although the textures of the mass matrices are completely different, the evolution of neutrino mass and mixing parameters is found to display approximately the same pattern. For both normal hierarchy and inverted hierarchy spectrum, the quantum corrections to both atmospheric and reactor neutrino mixing angles are so small that they can be neglected. The evolution of the solar mixing angle $\theta_{12}$ depends on $\tan\beta$ and neutrino mass spectrum, the deviation from its tri-bimaximal value could be large. Taking into account the renormalization group running effect, the neutrino spectrum is constrained by experimental data on $\theta_{12}$ in addition to the self-consistency conditions of the models, and the inverted hierarchy spectrum is disfavored for large $\tan\beta$. The evolution of light-neutrino masses is approximately described by a common scaling factor.Comment: 23 pages, 6figure