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.