Neutrino Bilarge Mixing and Flavor Physics in the Flipped SU(5) Model

Abstract

We have constructed a specific supersymmetric flipped SU(5) GUT model in which bilarge neutrino mixing is incorporated. Because the up-type and down-type quarks in the model are flipped in the representations ten and five with respect to the usual SU(5), the radiatively generated flavor mixing in squark mass matrices due to the large neutrino mixing has a pattern different from those in the conventional SU(5) and SO(10) supersymmetric GUTs. This leads to phenomenological consequences quite different from SU(5) or SO(10) supersymmetric GUT models. That is, it has almost no impact on B physics. On the contrary, the model has effects in top and charm physics as well as lepton physics. In particular, it gives promising prediction on the mass difference, $ΔM_D$, of the $D-{\bar D}$ mixing which for some ranges of the parameter space with large $\tanβ$ can be at the order of $10^9 ~\hbar ~s^{-1}$, one order of magnitude smaller than the experimental upper bound. In some regions of the parameter space $ΔM_D$ can saturate the present bound. For these ranges of parameter space, $t \to u,c+h^0$ can reach $10^{-5}-10^{-6}$ which would be observed at the LHC and future $γ-γ$ colliders.