The breakdown of $E_6$ gauge symmetry at high energies may lead to supersymmetric models based on the standard model gauge group together with extra $U(1{)}_{\psi }$ and $U(1{)}_{\chi }$ gauge symmetries. To ensure anomaly cancellation the particle content of these $E_6$ inspired models involves extra exotic states that generically give rise to nondiagonal flavor transitions and rapid proton decay. We argue that a single discrete ${\tilde{Z}}_2^H$ symmetry can be used to forbid tree-level flavor changing transitions, as well as the most dangerous baryon and lepton number violating operators. We present $5D$ and $6D$ orbifold grand unified theory constructions that lead to the $E_6$ inspired supersymmetric models of this type. The breakdown of $U(1{)}_{\psi }$ and $U(1{)}_{\chi }$ gauge symmetries that preserves $E_6$ matter parity assignment guarantees that ordinary quarks and leptons and their superpartners, as well as the exotic states which originate from 27 representations of $E_6$, survive to low energies. These $E_6$ inspired models contain two dark matter candidates and must also include additional TeV scale vectorlike lepton or vectorlike down-type quark states to render the lightest exotic quark unstable. We examine gauge coupling unification in these models and discuss their implications for collider phenomenology and cosmology.

• Received 9 October 2012

DOI:https://doi.org/10.1103/PhysRevD.87.015029