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

In the E6 inspired $U(1{)}_N$ extension of the minimal supersymmetric (SUSY) standard model (MSSM) a single discrete ${\tilde{Z}}_2^H$ symmetry permits suppressing rapid proton decay and non-diagonal flavour transitions. If matter parity and ${\tilde{Z}}_2^H$ 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.