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Compact Muon Solenoid
LHC, CERN

CMS-PAS-HIG-21-013
Evidence for off-shell Higgs boson production and first measurement of its width
Abstract: The first measurement of the Higgs boson (H) width is performed based on evidence for off-shell H production in the final state with two Z bosons decaying into either four charged leptons (e or $\mu$), or two charged leptons and two neutrinos. Results are based on data from the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of up to 140 fb$^{-1}$. The total size of off-shell H production beyond the Z boson pair production threshold is constrained at 95% confidence to be within the interval [0.0061, 2.0] times its standard model (SM) expectation. The scenario with no off-shell production is excluded at a confidence level larger than 99.9% (3.6 standard deviations). The width of the H boson is then extracted to be $\Gamma_{\mathrm{H}} = $ 3.2$_{-1.7}^{+2.4}$ MeV, in agreement with the SM expectation of 4.1 MeV. The data are also used to set new constraints on anomalous H boson couplings to massive electroweak vector boson pairs.
CMS Publications
Compact Muon Solenoid
LHC, CERN