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, mu, using data from pp collisions corresponding to an integrated luminosity of 5.1 fb(-1) at the center-of-mass energy of root s = 7 TeV and 19.7 fb(-1) at ffiffiffi root 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(-0.23)(+0.26) (stat)(-0.09)(+0.13) (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.