Observation of a new boson with mass near 125 GeV in pp collisions at sqrt(s) = 7 and 8 TeV

TL;DR

This paper reports the discovery of a new boson near 125 GeV at the LHC, consistent with the standard model Higgs, based on detailed analysis of multiple decay channels and coupling measurements.

Contribution

First observation of a boson consistent with the standard model Higgs at 125 GeV using combined decay channels and coupling analyses.

Findings

Discovery of a new boson near 125 GeV with 5 sigma significance

Mass measurement of 125.3 +/- 0.4 (stat) +/- 0.5 (syst) GeV

Results consistent with the standard model Higgs predictions

Abstract

A detailed description is reported of the analysis used by the CMS Collaboration in the search for the standard model Higgs boson in pp collisions at the LHC, which led to the observation of a new boson. The data sample corresponds to integrated luminosities up to 5.1 inverse femtobarns at sqrt(s) = 7 TeV, and up to 5.3 inverse femtobarns at sqrt(s) = 8 TeV. The results for five Higgs boson decay modes gamma gamma, ZZ, WW, tau tau, and bb, which show a combined local significance of 5 standard deviations near 125 GeV, are reviewed. A fit to the invariant mass of the two high resolution channels, gamma gamma and ZZ to 4 ell, gives a mass estimate of 125.3 +/- 0.4 (stat) +/- 0.5 (syst) GeV. The measurements are interpreted in the context of the standard model Lagrangian for the scalar Higgs field interacting with fermions and vector bosons. The measured values of the corresponding couplings are compared to the standard model predictions. The hypothesis of custodial symmetry is tested through the measurement of the ratio of the couplings to the W and Z bosons. All the results are consistent, within their uncertainties, with the expectations for a standard model Higgs boson.