Taking three right-handed Majorana neutrino masses $M^{ }_i$ to be partially non-degenerate, we make a new analysis of the Fukugita-Tanimoto-Yanagida ansatz and confront it with current neutrino oscillation data. We determine the parameter space for cases (A) $M^{ }_3 = M^{ }_2 \neq M^{ }_1$, (B) $M^{ }_2 = M^{ }_1 \neq M^{ }_3$ and (C) $M^{ }_1 = M^{ }_3 \neq M^{ }_2$, and examine their respective deviations from the original $M^{ }_1 = M^{ }_2 = M^{ }_3$ case. The numerical constraints on three light neutrino masses, three neutrino mixing angles and three CP-violating phases are also obtained, together with the predictions for the Jarlskog invariant of CP violation and the effective masses of the tritium beta decay and the neutrinoless double-beta decay.
Categories: hep-ph