Neutrino oscillations and other key issues in sypersymmetric SU(4)c × SU(2)L × SU(2)R Original Research Article

We try to gain an understanding of the recent Superkamiokande data on neutrino oscillations and several other important phenomenological issues within the framework of supersymmetric SU(4)c × SU(2)L × SU(2)R (э G422). By supplementing G422 with a U(1)−R symmetry we can provide an explanation of the magnitude MG (∼ 1016 GeV) of the G422-symmetry breaking scale, resolve the MSSM μ problem, and understand why proton decay has not been seen (τp ⪢ 1034 yr). The family dependent R-symmetry also helps provide an explanation of the charged fermion mass hierarchies as well as the magnitudes of the CKM matrix elements. Several additional heavy states in the mass range 104–107 GeV are predicted, and the MSSM parameter tan β turns out to be of order unity. The atmospheric neutrino problem is explained through νμ − ντ mixing with sin22θμτ ≅ 1. The resolution of the solar neutrino puzzle is via the small angle MSW oscillations and necessarily requires a sterile neutrino νs which, thanks to the R-symmetry, has a tiny mass.