S4 Flavor Symmetry of Quarks and Leptons in SU(5) GUT

We present an S4 flavor model to unify quarks and leptons in the framework of the SU(5) GUT. Three generations of 5-plets in SU(5) are assigned to 31 of S4, while the first and second generations of 10-plets in SU(5) are assigned to 2 of S4, and the third generation of 10-plets is assigned to 11 of S4. Right-handed neutrinos are also assigned to 2 for the first and second generations and to 11 for the third generation. By considering the vacuum alignments of relevant gauge singlet scalars, we predict the quark mixing as well as the tri-bimaximal mixing of neutrino flavors. In particular, the Cabbibo angle is predicted to be 15° in the limit of the vacuum alignment. We can improve the model to predict observed CKM mixing angles as well as the nonvanishing Ue3 of the neutrino flavor mixing.