Exploiting spin correlations in neutralino production and decay with polarized $e^-$ and $e^+$ beams

We study the production process $e^+ e^- \to \chi^0_1 \chi^0_2$ and the subsequent decay $\chi^0_2 \to \chi^0_1 l^+ l^-$ with polarized $e^+$ and $e^-$ beams, including the spin correlations between production and decay. We work out the advantages of polarizing both beams. We study in detail the angular distribution and the forward--backward asymmetry of the decay lepton as well as the opening angle distribution between the decay leptons. We investigate the dependence on the masses of $\tilde{e}_L$ and $\tilde{e}_R$ and on the mixing character of the neutralinos. In particular we study the dependence on the gaugino mass parameter $M_1$