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

The properties of a Higgs boson candidate are measured in the $Hensuremath{rightarrow}ZZensuremath{rightarrow}4ensuremath{ell}$ decay channel, with $ensuremath{ell}=e$, $ensuremath{mu}$, using data from $pp$ collisions corresponding to an integrated luminosity of $5.1text{ }text{ }{mathrm{fb}}^{ensuremath{-}1}$ at the center-of-mass energy of $sqrt{s}=7text{ }text{ }mathrm{TeV}$ and $19.7text{ }text{ }{mathrm{fb}}^{ensuremath{-}text{1}}$ at $sqrt{s}=8text{ }text{ }mathrm{TeV}$, 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 $125.6ifmmodepmelsetextpmfi{}0.4(text{stat})ifmmodepmelsetextpmfi{}0.2(text{syst})text{ }text{ }mathrm{GeV}$, and a total width $ensuremath{le}3.4text{ }text{ }mathrm{GeV}$ at the 95% confidence level. The production cross section of the new boson times its branching fraction to four leptons is measured to be ${0.93}_{ensuremath{-}0.23}^{+0.26}{(text{stat})}_{ensuremath{-}0.09}^{+0.13}(text{syst})$ 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.