Observation of an excess in the search for the Standard Model Higgs Boson at ALEPH

In 2000, 217 pb<super>&minus;1</super> of integrated luminosity were collected in the ALEPH detector at center-of-mass energies up to 210 GeV. The collected data have been analyzed for evidence of standard model Higgs boson production in all final state topologies arising from Higgs boson decays to fermions. A likelihood ratio calculation using the combined search results excludes Higgs boson masses less than 111.5 GeV/<italic>c</italic><super> 2</super> at 95% confidence level. An excess of candidate events with higher reconstructed Higgs boson masses, including three four- jet events strongly resembling Higgs boson decays, makes the observed dataset incompatible with the standard model expectation in the absence of Higgs boson production. Among all Higgs boson mass hypotheses, the maximum incompatibility is equivalent to an excess of 3.0 standard deviations. If part of the excess is attributed to standard model Higgs boson production, then the data are most compatible with a Higgs boson mass of 115 GeV/<italic>c</italic><super>2</super>.