| Abstract: | Searches were performed for topologies predicted by gauge-mediated supersymmetry breaking models (GMSB). All possible lifetimes of the next-to-lightest SUSY particle (NLSP), either the lightest neutralino or slepton, decaying into the lightest SUSY particle, the gravitino, were considered. No evidence for GMSB signatures was found in the OPAL data sample collected at centre-of-mass energies up to $sqrt{s}=209 mathrm{GeV}$ at LEP. Limits on the product of the production cross-sections and branching fractions are presented for all search topologies. To test the impact of the searches, a complete scan over the parameters of the minimal model of GMSB was performed. NLSP masses below $53.5 mathrm{GeV}/c^2$ in the neutralino NLSP scenario, below $87.4 mathrm{GeV}/c^2$ in the stau NLSP scenario and below $91.9 mathrm{GeV}/c^2$ in the slepton co-NLSP scenario are excluded at 95% confidence level for all NLSP lifetimes. The scan determines constraints on the universal SUSY mass scale Λ from the direct SUSY particle searches of Λ>40, 27, 21, 17, $15 mathrm{GeV}/c^2$ for messenger indices N=1,2,3,4,5 for all NLSP lifetimes. |
