Fermion masses and mixing within a SU(3) family symmetry model with five sterile neutrinos

Abstract

Within a broken local vector-like SU(3) family symmetry, we address the problem of quark masses and mixing in a framework with five sterile neutrinos. Heavy fermions, top and bottom quarks and tau lepton become massive at tree level from See-saw mechanisms implemented by the introduction of a new set of SU(2)_L weak singlets vector-like fermions U,D,E,N, with N a neutral lepton. The fermion content also include three right handed neutrinos introduced to cancel anomalies. Therefore, in this scenario light quarks and leptons, including active neutrinos and a light O(eV) sterile neutrino, become massive from radiative loop corrections mediated by the massive SU(3) gauge bosons. We provide a parameter space region where this framework can accommodate the known hierarchical spectrum of quark masses and mixing, the charged lepton masses and simultaneously suppress properly the current experimental constraints on Ko − \bar{Ko} and Do − \bar{Do} meson mixing. We also report the non-unitary, (VCKM)_{4×4} and (UPMNS)_{4×8}, quark and lepton mixing matrices. In addition, we find out that the mass of the SU(2)_L weak singlet vector-like D quark introduced in this scenario may lie within a few TeV's region, and hence within current LHC possibilities.