Light neutrino masses and mixing angles in SO(10) with realistic flavor structure, and the solar neutrino problem (original) (raw)

The fight neutrino mass spectrum and their mixing angles are investigated in a class of SO(10) models with GRSY seesaw mechanism. The models are motivated by a recent proposal on the structure of the Yukawa couplings postulated from the observed KM angles and the strong CP problem. The scale of GRSY seesaw mechanism is found to be bounded from above by the invisible axion scale, leading to a lower bound on the light neutrino masses, if the strong CP problem is solved by the standard Peccei-Quirm mechanism with the invisible axion. The main results on the light neutrino masses are: 0.18 eV ~< m~3 ~< 100 eV, m,,1/m,, 2 = O(mu/mc), and m,,2/m~3 =O((mc/mt)(1/mum¢/mt)) for the non-hierarchical structure of the right-handed neutrino mass matrix (MN), and m,,Jm~3 = O(mc/mt) for the hierarchical structure of M N. The mixing angles are predicted to be: