Spin correlations in the production and subsequent decay of neutralinos - art. no. 015016

We study the process e-e+ --> <(chi)over tilde>(0)(1)<(chi)over tilde>(0)(2 ) with the subsequent decay <(chi)over tilde>(0)(2) --> <(chi)over tilde>(0 )(1)l(+)l(-) taking into account the complete spin correlations. We give th e analytical formulas for the differential cross section and present numeri cal results for the lepton angular distribution and the distribution of the opening angle between the outgoing leptons for the CERN LEP2 energy of roo t s = 193 GeV and for root s = 500 GeV. We examine three representative mix ing scenarios in the MSSM and also study the influence of the common scalar mass parameter mo on the shape of the distributions. For the lepton angula r distribution, the effect of the spin correlations amounts to up to 20% fo r lower energies. We find that the opening angle distribution is suitable f or distinguishing between Higgsino-like and gaugino-like neutralinos. The s hape of the lepton angular distribution is very sensitive to the mixing in the gaugino sector and to the Value of mo. For higher energies, it is also suitable for distinguishing between Higgsino-like and gaugino-like neutrali no.