Neutrino masses and mixing within a SU(3) family symmetry model with one or two light sterile neutrinos

الأصل · EN

We report a global fit of parameters for fermion masses and mixing, including light sterile neutrinos, within a local vector SU(3) family symmetry model. In this scenario, ordinary heavy fermions, top and bottom quarks and tau lepton, become massive at tree level from Dirac See-saw mechanisms implemented by the introduction of a new set of SU(2)ₗ weak singlet vector-like fermions, U,D,E,N, with N a sterile neutrino. The Nₗ,ᵣ sterile neutrinos allow the implementation of a 8× 8 general tree level See-saw Majorana neutrino mass matrix with four massless eigenvalues. Hence, light fermions, including light neutrinos obtain masses from one loop radiative corrections mediated by the massive SU(3) gauge bosons. This BSM model is able to accommodate the known spectrum of quark masses and mixing in a 4× 4 non-unitary VCKM as well as the charged lepton masses. The explored parameter space region provide the vector-like fermion masses: MD ≈ 914.365 GeV, Mᵤ ≈ 1.5 TeV, Mₑ ≈ 5.97 TeV, SU(3) family gauge boson masses of O (1-10) TeV, the neutrino masses (m₁, m₂, m₃, m₄, m₅, m₆, m₇, m₈)= (0,0.0085, 0.049, 0.22, 3.21, 1749.96,1× 10⁸, 1× 10⁹) eV, with the squared neutrino mass differences: m₂²-m₁² ≈ 7.23 × 10⁻⁵ eV², m₃²-m₁² ≈ 2.4 × 10⁻³ eV², m₄²-m₁² ≈ 0.049 eV², m₅²-m₁² ≈ 10.3 eV². We also show the corresponding UPMNS lepton mixing matrix. However, the neutrino mixing angles are extremely sensitive to parameter space region, and an improved and detailed analysis is in progress.