All fermion masses and mixings in an intersecting D-brane world

Abstract

It is shown that neutrino mixing angles which are consistent with current experimental observations may be naturally obtained in a Pati-Salam model constructed from intersecting D6 branes on a T6/(Z2×Z2) orientifold. The Dirac mass matrices in the model are naturally the same as those which are obtained by imposing a Δ(27) flavor symmetry, which allows for near-tribimaximal mixing in the neutrino sector. In addition, it is possible to obtain the correct mass matrices for quarks and charged leptons, as well as nearly the correct CKM matrix. An RGE analysis of the neutrino mass parameters, including the seesaw mechanism assuming a specific form for the right-handed neutrino mass matrix is performed, and it is found that the neutrino mixing angles at the electroweak scale are θ12=35.0°, θ23=47.1°, and θ13=8.27°. In addition, the neutrino mass-squared differences are found to be Δm322=0.00252 eV2 and Δm212=0.0000739 eV2 with m1=0.0146 eV, m2=0.0170 eV, m3=0.0530 eV, and Σmi=0.0846 eV. These results depend slightly upon the scale at which the RGE running goes from being that of the MSSM to that of the SM, which we interpret to be the lightest stop mass. The best agreement with experimental data is for m˜t1≈4.28 TeV. This suggests that the superpartners which produce the strongest signal in a hadron collider are just out of reach at the LHC.