SUSY breaking and CP violation in E6 grand unified theory with horizontal symmetry

Abstract

We introduce various attractive features of E6 grand unified theory (GUT). First of all, we remind that in SU(5) GUT, the various hierachical structures of the masses and mixings of quarks and leptons can be explained by introducing an assuption. We show that E6 GUT can naturally explain the assumption. In other words, in E6 GUT, from only one basic Yukawa hierarchy corresponding up‐type quark Yukawa couplings, all the other Yukawa hierachies can be obtained. Moreover, if we introduce the horizontal symmetry, SU(2)H or SU(3)H which can unify all the three generation quarks and leptons, not only the SUSY flavor problem but also the SUSY CP problem can be solved by spontaneous CP violation. The constraints from the chromo electric dipole moments can be satisfied in a non‐trivial way. It is non‐trivial that the discrete symmetry Z12, which is required to avoid a problem in solving the SUSY CP problem in this model, is consistent with the E6 Higgs sector in which the doublet‐triplet splitting problem can be solved with the anomalous U(1) gauge symmetry. The E6 GUT with the horizontal symmetry predicts peculiar sfermion masses which can be tested in future experiments on lepton flavor violations and on CP violation in B mesons. Some of them can be tested in near future experiments. This talk is based on various papers collaborated with M. Bando, T. Yamashita, S.‐G. Kim, K. Sakurai, A. Matsuzaki, T. Yoshikawa, and M. Ishiduki[1, 2, 3, 4, 5].