Mass limits for a standard model Higgs Boson in e+e− collisions at LEP

Abstract A search for the minimal standard model Higgs boson has been performed with data from e + e − collisions in the OPAL detector at LEP. The analysis is based on 825 nb −1 of data taken at centre-of-mass energies between 88.3 and 95.0 GeV. The search concentrated on the reactions e + e − →(e + e − or μ + μ − or v v )H 0 ,H 0 →( q q or τ + τ − ) , for Higgs masses above 3 GeV/ c 2 . No Higgs boson candidates have been observed. The present study excludes the existence of a standard model H 0 with mass in the range 3.0⩽ m H ⩽19.3 GeV/ c 2 at the 95% confidence level.