Measurement of the properties of a Higgs boson in the four-lepton final state

Abstract

The properties of a Higgs boson candidate are measured in the H→ZZ→4ℓ decay channel, with ℓ=e, μ, using data from pp collisions corresponding to an integrated luminosity of 5.1 fb−1 at the center-of-mass energy of √s=7 TeV and 19.7 fb−1 at √s=8 TeV, recorded with the CMS detector at the LHC. The new boson is observed as a narrow resonance with a local significance of 6.8 standard deviations, a measured mass of 125.6±0.4(stat)±0.2(syst) GeV, and a total width ≤3.4 GeV at the 95% confidence level. The production cross section of the new boson times its branching fraction to four leptons is measured to be 0.93+0.26−0.23(stat)+0.13−0.09(syst) times that predicted by the standard model. Its spin-parity properties are found to be consistent with the expectations for the standard-model Higgs boson. The hypotheses of a pseudoscalar and all tested spin-1 boson hypotheses are excluded at the 99% confidence level or higher. All tested spin-2 boson hypotheses are excluded at the 95% confidence level or higher.