A search for acoplanar pairs of leptons or jets in Z0 decays. Mass limits on supersymmetric particles

Abstract We have searched for Z 0 decays into acoplanar pairs of leptons or jets. The data were recorded with the OPAL detector during an energy scan around the Z 0 peak and correspond to about 17000 produced Z 0, s. We have determined model independent limits on branching ratios for the Z 0 to decay into pairs of heavy particles with subsequent decays leading to the above topologies. In the context of supersymmetric models, mass bounds close to the kinematic limit were obtained for the scalar leptons, ẽ, gm, gt, and for the chargino, X ± .