Search for new particles with the OPAL detector

Data collected in 1989 with the Opal detector (Omni Purpose Apparatus for LEP [1]) allow powerful searches for new particles. To the noticeable exception of the production of the Higgs boson, the accumulated statistics of ∼ 1.2pb-1 excludes new particles up to the kinematical limit for most of the considered processes. We briefly summarize here the search techniques and the limits we get for sequential quarks t and b', sequential heavy leptons L±, neutral heavy leptons L0, SUSY particles (sleptons antic, antiμ and antiτ, photino antiγ and chargino antiχ±), Higgs bosons (standard model Higgs ll0, minimal SUSY Higgses h0 and A0, charged Higgs ll±), excited leptons l*, and finally some rare decays of the Z0