Democratic Neutrino Mixing Reexamined

Abstract

We reexamine the democratic neutrino mixing ansatz, in which the mass matrices of charged leptons and Majorana neutrinos arise respectively from the explicit breaking of S(3)_L x S(3)_R and S(3) flavor symmetries. It is shown that a democracy term in the neutrino sector can naturally allow the ansatz to fit the solar neutrino mixing angle θ_sun \approx 33^\circ. We predict \sin^2 2θ_atm \approx 0.95 for atmospheric neutrino mixing and J \approx 1.2% for leptonic CP violation in neutrino oscillations without any fine-tuning. Direct relations between the model parameters and experimental observables are also discussed.