October 27, 2001 | ALEPH, DELPHI, L3 and OPAL Collaborations
The LEP working group for Higgs boson searches, comprising the ALEPH, DELPHI, L3, and OPAL collaborations, has combined data from e+e- collisions at energies between 189 and 209 GeV to search for the Standard Model (SM) Higgs boson. The combined data set amounts to 2465 pb^-1, with 542 pb^-1 collected above 206 GeV. The searches were performed using various decay channels, including four-jet, missing energy, leptonic, and tau lepton final states.
The likelihood analysis revealed a preference for a Higgs boson with a mass of 115.6 GeV, corresponding to a 95% confidence level lower bound of 114.1 GeV. The probability for the background to generate the observed effect at this mass is 3.4%. The excess observed at this mass is primarily driven by the ALEPH data and the four-jet final state.
The results are subject to uncertainties, including systematic errors and technical approximations. The LEP collaborations have addressed these uncertainties through various tests and analyses, ensuring the robustness of the findings. The conclusion emphasizes that the observed excess is consistent with the SM Higgs boson hypothesis, with a significance of about two standard deviations.The LEP working group for Higgs boson searches, comprising the ALEPH, DELPHI, L3, and OPAL collaborations, has combined data from e+e- collisions at energies between 189 and 209 GeV to search for the Standard Model (SM) Higgs boson. The combined data set amounts to 2465 pb^-1, with 542 pb^-1 collected above 206 GeV. The searches were performed using various decay channels, including four-jet, missing energy, leptonic, and tau lepton final states.
The likelihood analysis revealed a preference for a Higgs boson with a mass of 115.6 GeV, corresponding to a 95% confidence level lower bound of 114.1 GeV. The probability for the background to generate the observed effect at this mass is 3.4%. The excess observed at this mass is primarily driven by the ALEPH data and the four-jet final state.
The results are subject to uncertainties, including systematic errors and technical approximations. The LEP collaborations have addressed these uncertainties through various tests and analyses, ensuring the robustness of the findings. The conclusion emphasizes that the observed excess is consistent with the SM Higgs boson hypothesis, with a significance of about two standard deviations.