Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC


Chatrchyan S., Khachatryan V., Sirunyan A. M. , Tumasyan A., Adam W., Aguilo E., ...More

PHYSICS LETTERS B, vol.716, no.1, pp.30-61, 2012 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 716 Issue: 1
  • Publication Date: 2012
  • Doi Number: 10.1016/j.physletb.2012.08.021
  • Title of Journal : PHYSICS LETTERS B
  • Page Numbers: pp.30-61
  • Keywords: CMS, Physics, Higgs, MODEL HIGGS-BOSON, STANDARD MODEL, PP COLLISIONS, ELECTROWEAK CORRECTIONS, PARTON DISTRIBUTIONS, BROKEN SYMMETRIES, QCD CORRECTIONS, SEARCH, COLLIDERS, SPECTRUM

Abstract

Results are presented from searches for the standard model Higgs boson in proton-proton collisions at root 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 fb(-1) at 7 TeV and 5.3 fb(-1) at 8 TeV. The search is performed in five decay modes: gamma gamma, ZZ, W+W-, tau(+)tau(-), and b (b) over 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. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.