Leptogenesis and Dark Matter–Nucleon Scattering Cross Section in the SE 6 SSM.

The E 6 -inspired extension of the minimal supersymmetric (SUSY) standard model (MSSM) with an extra U (1) N gauge symmetry, under which right-handed neutrinos have zero charge, involves exotic matter beyond the MSSM to ensure anomaly cancellation. We consider the variant of this extension (SE 6 SSM) in which the cold dark matter is composed of the lightest neutral exotic fermion and gravitino. The observed baryon asymmetry can be induced in this case via the decays of the lightest right-handed neutrino/sneutrino into exotic states even for relatively low reheating temperatures T R ≲ 10 6 − 7 G e V . We argue that there are some regions of the SE 6 SSM parameter space, which are safe from all current constraints, and discuss the implications of this model for collider phenomenology. [ABSTRACT FROM AUTHOR]