Spin Correlations in Production and Subsequent Decay of Neutralinos

We study the process e^{-}e^{+} \to \tilde{\chi}^0_1\tilde{\chi}^0_2 with the subsequent decay \tilde{\chi}^0_2 \to \tilde{\chi}^0_1 \ell^{+}\ell^{-} taking into account the complete spin correlations. We give the analytical formulae for the differential cross section and present numerical results for the lepton angular distribution and the distribution of the opening angle between the outgoing leptons for the LEP2 energy of $\sqrt{s}=182$ GeV. We examine three representative mixing scenarios in the MSSM and also study the influence of the common scalar mass parameter $m_0$ on the shape of the distributions. For the lepton angular distribution the effect of the spin correlations amounts to up to 20%. We find that the opening angle distribution is suitable for distinguishing between Higgsino-like and gaugino-like neutralinos. The shape of the lepton angular distribution is very sensitive to the mixing in the gaugino sector and to the value of m_0