Exceptional Supersymmetric Standard Model

Abstract

We discuss some phenomenological aspects of an $E_6$ inspired supersymmetric standard model with an extra $U(1)_{N}$ gauge symmetry under which right-handed neutrinos have zero charge, allowing a conventional see-saw mechanism. The $μ$ problem is solved in a similar way to the NMSSM, but without the accompanying problems of singlet tadpoles or domain walls. The above exceptional supersymmetric standard model (ESSM) involves the low energy matter content of three 27 representations of $E_6$, which is broken at the GUT scale, and allows gauge coupling unification due to an additional pair of Higgs-like doublets. The ESSM predicts a $Z'$ boson and exotic quarks which, if light enough, will provide spectacular new physics signals at the LHC. We study the LHC phenomenology of the $Z'$ and extra quarks, including their production and decay signatures particular to the ESSM. We also discuss the two-loop upper bound on the mass of the lightest CP-even Higgs boson, and show that it can be significantly heavier than in either the MSSM or the NMSSM.