| Summary: | In some supersymmetric models, the gluino (g̃) is predicted to be light and stable. In that case, it would hadronize to form R-hadrons. In these models, the missing energy signature of the lightest supersymmetric particle is no longer valid, even if R-parity is conserved. Therefore, such a gluino is not constrained by hadron collider results, which looked for the decay g̃ → qq̄10. Data collected by the DELPHI detector in 1994 at 91.2 GeV have been analysed to search for qq̄g̃g̃ events. No deviation from Standard Model predictions is observed and a gluino mass between 2 and 18 GeV/c2 is excluded at the 95% confidence level in these models. Then, R-hadrons produced in the squark decays were searched for in the data collected by DELPHI at the centre-of-mass energies of 189 to 208 GeV, corresponding to an overall integrated luminosity of 609 pb-1. The observed number of events is in agreement with the Standard Model predictions. Limits at 95% confidence level are derived on the squark masses from the excluded regions in the plane (mq̄1,mg̃): mt̃1 > 90 GeV/c2, and mb̃1 > 96 GeV/c2 for purely left squarks. mt̃1 > 87 GeV/c2, and mb̃1 > 82 GeV/c2 independent of the mixing angle.
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