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A total of 628 pb-1 of data collected with the ALEPH detector at centre-of-mass
energies from 189 to 209 GeV is analysed in the search for gauge
mediated supersymmetry breaking (GMSB) topologies. In this framework, a
novel search for six-lepton final states when the stau is the
next-to-lightest supersymmetric particle (NLSP) and has negligible
lifetime is performed. Other possible signatures at LEP are studied and
the ALEPH final results described for two acoplanar photons,
non-pointing single photons, acoplanar leptons, large impact parameter
leptons, detached slepton decay vertices, heavy stable charged sleptons
and multi-leptons plus missing energy final states. No evidence is found
for new phenomena, and lower limits on the masses of the relevant
supersymmetric particles are derived. A scan of a minimal GMSB parameter
space is performed and lower limits are set for the NLSP mass at 54 GeV
and for the mass scale parameter Lambda at 10 TeV, independent of the
NLSP lifetime. Including the results from the neutral Higgs boson
searches, a NLSP mass limit of 77 GeV is obtained and values of Lambda
up to 16 TeV are excluded.
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