Neutralinos in E6 inspired supersymmetric U(1)' models

The neutralino sector in E6 inspired supersymmetric models with extra neutral gauge bosons and singlet Higgs fields contains additional gaugino and singlino states compared to the MSSM. We discuss the neutralino mixing in rank-5 and rank-6 models and analyze the supersymmetric parameter space where the light neutralinos have mainly singlino or MSSM character. The neutralino character, resonance effects of the new gauge bosons and, assuming mSUGRA-type RGEs, different selectron masses lead to significant differences between the MSSM and the extended models in neutralino production at an e+e- linear collider. Beam polarization may improve the signatures to distinguish between the models. In an appendix, we present the mass terms of the gauge bosons, charginos and sfermions which show a significant different mass spectrum than in the MSSM and give all relevant neutralino couplings. (orig.)