On the Suppression of the Dark Matter-Nucleon Scattering Cross Section in the SE$_6$SSM

Abstract

In the E6 inspired $U(1)_N$ extension of the minimal supersymmetric (SUSY) standard model (MSSM) a single discrete $\tilde{Z}^{H}_2$ symmetry permits suppressing rapid proton decay and non-diagonal flavour transitions. If matter parity and $\tilde{Z}^{H}_2$ symmetry are preserved this SUSY model (SE4-6$SSM) may involve two dark matter candidates. In this article we study a new modification of the SE6SSM in which the cold dark matter is composed of gravitino and the lightest neutral exotic fermion. We argue that in this case the dark matter-nucleon scattering cross section can be considerably smaller than the present experimental limit.