Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
S. Chatrchyana, V. Khachatryana, A. M. Sirunyana, A. Tumasyana, W. Adamb, E. Aguilób, T. Bergauerb, M. Dragicevicb, J. Eröb, Christian W. Fabjanb, M. Friedlb, Rudolf Konrad Fruhwirthb, V. M. Gheteb, J. Hammerb, Michael J. R. Hochb, N. Hörmannb, J. Hrubecb, M. Jeitlerb, W. Kiesenhoferb, V. Knünzb, M. Krammerb, Ilse Krätschmerb, Dietrich Likob, W. Majerottob, I. Mikulecb, M. Pernickab, B. Rahbaranb, C. Rohringerb, H. Rohringerb, R. Schöfbeckb and 2861 others
- aYerevan Physics Institute, Yerevan, Armenia
- bInstitut für Hochenergiephysik der OeAW, Wien, Austria
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Abstract
Results are presented from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s) = 7 and 8 TeV in the Compact Muon Solenoid experiment at the LHC, using data samples corresponding to integrated luminosities of up to 5.1 inverse femtobarns at 7 TeV and 5.3 inverse femtobarns at 8 TeV. The search is performed in five decay modes: gamma gamma, ZZ, WW, tau tau, and b b-bar. An excess of events is observed above the expected background, with a local significance of 5.0 standard deviations, at a mass near 125 GeV, signalling the production of a new particle. The expected significance for a standard model Higgs boson of that mass is 5.8 standard deviations. The excess is most significant in the two decay modes with the best mass resolution, gamma gamma and ZZ; a fit to these signals gives a mass of 125.3 +/- 0.4 (stat.) +/- 0.5 (syst.) GeV. The decay to two photons indicates that the new particle is a boson with spin different from one.