Search for the minimal standard model Higgs boson

Abstract A search for the Minimal Standard Model Higgs boson (H 0 ) has been performed with data from e + e − collisions collected by the OPAL detector at LEP. The search was made for events of the types e + e − →( e + e − ,μ + μ − or ν ν ) H 0 , H 0 → q q and was based on approximately 78 pb −1 of data taken at center-of-mass energies between 88 and 95 GeV in the years 1990–1993. The present study, combined with previous OPAL publications, excludes the existence of a Minimal Standard Model Higgs boson with mass below 56.9 GeV at the 95% confidence level.