Abstract
Constraints on the lifetime and width of the Higgs boson are obtained from H to ZZ to 4 lepton events using data recorded by the CMS experiment during the LHC run 1 with an integrated luminosity of 5.1 and 19.7 inverse femtobarns at a center-of-mass energy of 7 and 8 TeV, respectively. The measurement of the Higgs boson lifetime is derived from its flight distance in the CMS detector with an upper bound of tau[H] < 1.9E-13 s at the 95% confidence level (CL), corresponding to a lower bound on the width of Gamma[H] > 3.5E-9 MeV. The measurement of the width is obtained from an off-shell production technique, generalized to include anomalous couplings of the Higgs boson to two electroweak bosons. From this measurement, a joint constraint is set on the Higgs boson width and a parameter f[LQ] that expresses an anomalous coupling contribution as an on-shell cross-section fraction. The limit on the Higgs boson width is Gamma[H] < 46 MeV with f[LQ] unconstrained and Gamma[H] < 26 MeV for f[LQ] = 0 at the 95% CL. The constraint f[LQ] < 3.8E-3 at the 95% CL is obtained for the expected standard model Higgs boson width.
Highlights
The discovery of a new boson with mass of about 125 GeV by the ATLAS and CMS experiments [1,2,3] at the CERN LHC provides support for the standard model (SM) mechanism with a field responsible for generating the masses of elementary particles [4,5,6,7,8,9]
The measurement of the H boson lifetime in this paper is derived from its flight distance in the CMS detector [19], and the measurement of the width is obtained from the offshell production technique, generalized to include anomalous couplings of the H boson to two electroweak bosons, WW and ZZ
Following the formalism in Eq (4) for spin-zero and including nonzero spin hypotheses, JHUGen simulations for a variety of H boson production and decay (H → ZZ=ZγÃ=γÃγà → 4l) modes have been generated with SM and BSM couplings to validate model independence of the lifetime analysis
Summary
The discovery of a new boson with mass of about 125 GeV by the ATLAS and CMS experiments [1,2,3] at the CERN LHC provides support for the standard model (SM) mechanism with a field responsible for generating the masses of elementary particles [4,5,6,7,8,9]. No direct experimental limit on the H boson lifetime was set, and the possible presence of anomalous couplings was not considered in the constraints on the H boson width The measurement of the H boson lifetime in this paper is derived from its flight distance in the CMS detector [19], and the measurement of the width is obtained from the offshell production technique, generalized to include anomalous couplings of the H boson to two electroweak bosons, WW and ZZ From the latter measurement, a joint constraint is set on the H boson width and a parameter that quantifies an anomalous coupling contribution as an onshell cross-section fraction.
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