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

TL;DR

This paper reports the discovery of a new boson at 125 GeV by the CMS experiment at the LHC, based on multiple decay channels and significant excess over background, consistent with the Higgs boson predicted by the Standard Model.

Contribution

First observation of a new boson at 125 GeV with evidence across multiple decay modes, supporting the discovery of the Higgs boson at the LHC.

Findings

Excess of events with 5.0 sigma significance at 125 GeV

Mass measurement of 125.3 GeV with uncertainties

Decay to two photons indicates a boson with spin not equal to one

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.