  Data collected by the OPAL detector at LEP up to the highest energies of 209
GeV are analyzed to search for evidence of supersymmetric (SUSY) particle
production. Chargino pair-production and neutralino associated production are
considered in models where supersymmetry breaking is mediated by gravitational
interactions. The focus of the searches is on topologies arising when scalar
fermions are heavy and the lightest neutralino is the lightest SUSY particle
(LSP). Searches for topologies predicted by gauge-mediated SUSY breaking (GMSB)
models are also discussed. In these models the LSP is the gravitino and the
phenomenology is driven by the nature of the next-to-lightest SUSY particle
(NLSP) which is either the lightest neutralino, stau or mass degenerate
sleptons. As the NLSP decay length is effectively unconstrained, all possible
values are considered and results independent of the NLSP lifetime are
presented for all relevant final states including direct NLSP pair-production
and NLSP production via cascade decays of heavier SUSY particles. None of the
searches shows evidence for SUSY particle production. Cross-section limits are
presented at the 95% confidence level both for direct NLSP production and, for
the first time, also for cascade decays. These are then interpreted in the
framework of minimal theoretical models. Large areas of the accessible
parameter space are excluded and constraints on the mass of the SUSY particles
are derived.
