Neutrino mass matrix with U(2) flavor symmetry and its test in neutrino oscillation experiments

The three modified neutrino mass matrices in the SU(5) × U(2) model are studied focusing on the neutrino oscillation experiments. The model could be reconcile with the data of LSND. In the case of 〈φ1〉 6 = 0, the heaviest neutrino could be the hot dark matter; m3 ≥ 1eV, which means that CHORUS/NOMAD will find neutrino oscillations. In the special case of a = 1, which is a coefficient of 22 entry in the right-handed Majorana mass matrix, the atmospheric neutrino anomaly is explained by the large νμ − ντ oscillation. The long baseline experiments are expected to detect signatures of the neutrino oscillation even if the atmospheric neutrino anomaly is not due to the neutrino oscillation. However, it is found that the model cannot solve the solar neutrino deficit. E-mail address: [email protected]