Search for charginos, neutralinos and gravitinos in e+ e- interactions at S**(1/2) = 183-GeV

An update of the searches for charginos and neutralinos is presented, based on a data sample corresponding to the 53.9 pb−1 recorded by the DELPHI detector in 1997, at a centre-of-mass energy of 183 GeV. No evidence for a signal was found. The lower mass limits are 4–5 GeV/c2 higher than those obtained at a centre-of-mass energy of 172 GeV. The (μ,M2) domain excluded by combining the neutralino and chargino searches implies a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 29.1 GeV/c2 for tanβ≥ 1.