Running neutrino masses and mixing in a SU(4)×SU(2)²× U(1)_Xmodel

Abstract

In this talk, we discuss the implications of the renormalization group equations for the neutrino masses and mixing angles in a supersymmetric string-inspired SU(4)×SU(2)L×SU(2)R×U(1)X model with matter in fundamental and antisymmetric tensor representations only. The quark, charged lepton and neutrino Yukawa matrices are distinguished by different Clebsch-Gordan coefficients due to contracting over SU(4) and SU(2)R indices. In order to permit for a more realistic, hierarchical light neutrino mass spectrum with bi-large mixing a second U (1)X breaking singlet with fractional charge is introduced. By numerical investigation we find a region in the model parameter space where the neutrino mass-squared differences and mixing angles at low energy are consistent with experimental data.