Direct search for the Standard Model Higgs boson

For twelve years, LEP revolutionized the knowledge of electroweak symmetry breaking within the standard model, and the direct discovery of the Higgs boson would have been the crowning achievement. Searches at the Z resonance and above the W⁺W⁻ threshold allowed an unambiguous lower limit on the mass of the standard model Higgs boson to set be at 114.1 GeV·c⁻². After years of efforts to push the LEP performance far beyond the design limits, hints of what could be the first signs of the existence of a 115 GeV·c⁻² Higgs boson appeared in June 2000, were confirmed in September, and were then confirmed again in November. An additional six-month period of LEP operation was enough to provide a definite answer, with an opportunity to make a fundamental discovery of prime importance. To cite this article: P. Janot, M. Kado, C. R. Physique 3 (2002) 1193–1202.