Searches for gauge-mediated supersymmetry breaking topologies in e +e- collisions at centre-of-mass energies up to →s = 209 GeV

Searches were performed for topologies predicted by gauge-mediated supersymmetry breakingmodels (GMSB). All possible lifetimes of the next-to-lightest SUSY particle (NLSP), either the lightest neutralinoor 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 root s = 209 GeV at LEP. Limits on the product of the production cross-sections and branching fractionsare presented for all search topologies. To test the impact of the searches, a complete scan over the parameters of the minimal modelof GMSB was performed. NLSP masses below 53.5 GeV/c(2) in the neutralinoNLSP scenario, below 87.4 GeV/c(2) in the stau NLSP scenario and below 91.9 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 Lambda from the direct SUSY particle searches of Lambda > 40, 27, 21, 17, 15 TeV/c(2) for messenger indices N = 1, 2, 3, 4, 5 for all NLSP lifetimes.