A Review of the Exceptional Supersymmetric Standard Model

TL;DR

This review discusses the exceptional supersymmetric standard model (E6SSM), highlighting its unique features, particle content, symmetry considerations, and potential signatures at the LHC, within the context of grand unified theories and string-inspired models.

Contribution

It provides a comprehensive overview of the E6SSM, emphasizing its novel particle content, symmetry properties, and phenomenological implications compared to traditional SUSY models.

Findings

E6SSM includes exotic matter beyond MSSM.

Suppression of flavor-changing and proton decay processes achieved.

Potential LHC signatures of exotic states discussed.

Abstract

Local supersymmetry (SUSY) provides an attractive framework for the incorporation of gravity and unification of gauge interactions within Grand Unified Theories (GUTs). Its breakdown can lead to a variety of models with softly broken SUSY at low energies. In this review article we focus on the SUSY extension of the Standard Model (SM) with an extra U(1)_{N} gauge symmetry originating from a string-inspired E_6 grand unified gauge group. Only in this U(1) extension of the minimal supersymmetric standard model (MSSM) inspired by E_6 GUTs the right-handed neutrinos can be superheavy providing a mechanism for the generation of the lepton and baryon asymmetry of the Universe. The particle content of this exceptional supersymmetric standard model (E_6SSM) includes three 27 representations of the E_6 group, to ensure anomaly cancellation, plus a pair of SU(2)_W doublets as required for gauge coupling unification. Thus E_6SSM involves extra exotic matter beyond the MSSM. We consider symmetries that permit to suppress non-diagonal flavour transitions and rapid proton decay, as well as gauge coupling unification, the breakdown of the gauge symmetry and the spectrum of Higgs bosons in this model. The possible Large Hadron Collider (LHC) signatures caused by the presence of exotic states are also discussed.