Neutrino masses and bimaximal mixing

Solar and atmospheric neutrino anomalies are described by bimaximal mixing of three Majorana neutrinos. Neutrino oscillations in appearance νe⇌νμ,ντ and in disappearance νe long baseline and atmospheric experiments are sensitive to deviations from the ideal bimaximal mixing. It is suggested that these deviations may be dominated by a rotation in the electron–muon plane of the generation space. Simple seesaw models are described supporting this idea. The rotation angle is estimated from Fritzschʹs relation. Predictions are presented for oscillations in long baseline experiments, for solar neutrinos, and for the rates of neutrinoless double beta decays.