On the Fukugita-Tanimoto-Yanagida Ansatz with Partially Non-degenerate Right-handed Majorana Neutrinos

Abstract

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) $M_3^{}=M_2^{}\ne M_1^{}$, (B) $M_2^{}=M_1^{}\ne M_3^{}$ and (C) $M_1^{}=M_3^{}\ne M_2^{}$, 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.

Comments: 17 pages, 4 figures, references added, minor changes