Singlino-dominated Neutralinos in Extended Supersymmetric Models

We adopt the SUSY benchmark scenario SPS 1a in supersymmetric models where the Higgs sector is extended by singlet superfields. We consider light neutralinos with dominant singlino character whose couplings are generally suppressed. The cross sections for direct production of the singlino-dominated neutralinos can be of the order of several fb for singlet vevs of some TeV. Hence even exotic neutralinos which are not the LSP and are omitted in the decay chains of the other supersymmetric particles may be visible at a high luminosity linear e^+e^- collider. If, however, the LSP is singlino-dominated the decay width of the NLSP can be very small and displaced vertices exist for large singlet vacuum expectation values