Generalized Friedberg-Lee model for neutrino masses and leptonic CP violation from mu-tau symmetry breaking

Abstract

Assuming the Majorana nature of massive neutrinos, we generalize the Friedberg-Lee neutrino mass model to include CP violation in the neutrino mass matrix M_ν. The most general case with all the free parameters of M_νbeing complex is discussed. We show that a favorable neutrino mixing pattern (with θ_12 \approx 35.3^\circ, θ_23=45^\circ, θ_13 \neq 0^\circ and δ=90^\circ) can naturally be derived from M_ν, if it has an approximate or softly-broken μ-τsymmetry. We also point out a different way to obtain the nearly tri-bimaximal neutrino mixing pattern with δ=0^\circ and non-vanishing Majorana phases.

4 pages. Talk given by He Zhang at the 4th International Conference on Flavor Physics, 24-28 September 2007, Beijing (to appear in the proceedings)