Z₂-Singlino Dark Matter in a Portal-Like Extension of the Minimal Supersymmetric Standard Model

We propose a Z_2-stabilised singlino (\bar{\chi}) as a dark matter candidate in extended and R-parity violating versions of the supersymmetric standard model. \bar{\chi} interacts with visible matter via a heavy messenger field S, which results in a supersymmetric version of the Higgs portal interaction. The relic abundance of \bar{\chi} can account for cold dark matter if the messenger mass satisfies M_S \lsim 10^{4} GeV. Our model can be implemented in many realistic supersymmetric models such as the NMSSM and nMSSM.