Search for the standard model Higgs boson at LEP

Abstract

One of the missions of the LEP program was the search for the Standard Model Higgs Boson. The skillful operation of the machine in the year 2000, the final year of operation, has allowed the four collaborations ALEPH, DELPHI, L3 and OPAL to collect 536 pb −1 of data at center-of-mass energies of 206 GeV or higher. This data is used to probe the existence of the Higgs boson up to a mass of around 115 GeV. Tantalizing candidates have been observed in excess over the Standard Model predictions, but without enough statistical power to claim a discovery. A Higgs boson lighter than 114.4 GeV is hence excluded at 95% confidence level.