MEASURING SUSY PARAMETERS AT CERN LEP-II USING CHARGINO PRODUCTION AND DECAY

Previously, in the context of the minimal supersymmetric standard mode l (without a priori assumptions of parameter unification), we studied the constraints on weak-scale SUSY parameters from chargino production at CERN LEP II, using as observables m(<(chi)over tilde>1+/-), m(<(ch i)over tilde>10) the cross section and the leptonic branching fraction . Here, exploiting the high degree of polarization in chargino product ion, we add to our earlier work the forward-backward asymmetries of th e visible hadrons and leptons in chargino decays. For a chargino that is mostly gaugino, the parameter space can now be restricted to a smal l region; tan beta is constrained, the soft electroweak gaugino and el ectron sneutrino masses are determined to about 10%, and the sign of m u may be determined. Constraints for a chargino that is mostly Higgsin o are much weaker, but still disfavor the hypothesis that the chargino is mostly gaugino. For a chargino which is a roughly equal mixture of Higgsino and gaugino, we find intermediate results.