Abstract
The properties of a Higgs boson candidate are measured in the H to ZZ to 4l decay channel, with l = e, mu, using data from pp collisions corresponding to an integrated luminosity of 5.1 inverse femtobarns at the center-of-mass energy of sqrt(s) = 7 TeV and 19.7 inverse femtobarns at sqrt(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 less than 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-one boson hypotheses are excluded at the 99% confidence level or higher. All tested spin-two boson hypotheses are excluded at the 95% confidence level or higher.
Highlights
The standard model (SM) of particle physics [1,2,3,4,5]describes very successfully the electroweak and strong interactions of elementary particles over a wide range of energies
The energy of the electromagnetic calorimeter (ECAL) superclusters is corrected for the imperfect containment of the clustering algorithm, the electron energy not deposited in the ECAL, and leakage arising from showers near gaps between crystals or between ECAL modules
The irreducible four-lepton background arising from double-parton interactions (DPI), Z þ Drell-Yan (DY), is evaluated using PYTHIA 6.4.24 with the overall cross section calculated as σDPI 1⁄4 σZ · σDY=σpheno, where the pphffieffi nomenological effective cross section, measured at s 1⁄4 7 TeV, is σpheno 1⁄4 15 mb [107], and the cross sections σZ and σDY are taken from simulation
Summary
Describes very successfully the electroweak and strong interactions of elementary particles over a wide range of energies. Using 2011 about 5 fb−1 and about 5 of data fb−1 of apdffidffi itional data collected in the first half of 2012 at s 1⁄4 8 TeV, the ATLAS and CMS experiments have reported the discovery of a new boson at a mass around. The analysis of the H → ZZ → 4l channel is presented using the entire data set collected by the CMS experiment during the 2011–2012 LHC running period. A search is conducted for additional resonances compatible with the SM Higgs boson in the H → ZZ → 4l channel in the mass range 110–1000 GeV.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
