An A_5 Model for Four Lepton Generations

[[abstract]]We study the lepton sector of a four generations model based on the discrete flavor group A5 (the even permutation of five objects). The best features of the three family A4 model survive, including the tribimaximal pattern of three generation neutrino mixings. At leading order the three light neutrino mass relations of mν1=mν3 and mν2=0 are predicted. The splitting of the neutrino masses can be naturally obtained as a result of the breaking of A5 down to A4 and a degenerate spectrum is preferred in our model. In our A5 model, the electron mass is zero at tree level, but calculable through quantum corrections.[[notice]]補正完