Abstract :
It is shown that using non-Abelian horizontal gauge symmetry and anomalous U(1)A symmetry in grand unified theories (GUTs), realistic quark and lepton mass matrices including large neutrino mixings can be obtained, while the differences among the scalar fermion masses are sufficiently small for suppression of various flavor changing neutral current (FCNC) processes, especially in E6 GUT. Combining the Higgs sector, in which doublet–triplet splitting is realized, a complete E6×SU(3)H GUT, in which three generations are unified into a single multiplet, Ψ(27,3), is obtained.
