E6 inspired SUSY models with Custodial Symmetry

Abstract

The breakdown of E_6 within the supersymmetric (SUSY) Grand Unified Theories (GUTs) can result in SUSY extensions of the standard model (SM) based on the SM gauge group together with extra U(1) gauge symmetry under which right-handed neutrinos have zero charge. In these U(1)_N extensions of the minimal supersymmetric standard model (MSSM) a single discrete \tilde{Z}^H_2 symmetry may be used to suppress the most dangerous operators, that give rise to proton decay as well as non-diagonal flavour transitions at low energies. The SUSY models under consideration involves Z' and extra exotic matter beyond the MSSM. We discuss leptogenesis within this SUSY model and argue that the extra exotic states may lead to the non--standard Higgs decays.