A study of anomalous couplings of the Higgs boson to vector bosons and fermions is presented. The data were recorded by the CMS experiment at a center-of-mass energy of pp collisions at the LHC of 13 TeV and correspond to an integrated luminosity of 138 fb$^{-1}$. The study uses Higgs boson candidates produced mainly in gluon fusion or electroweak vector boson fusion at the LHC that subsequently decay to a pair of $\tau$ leptons. Matrix-element and machine-learning techniques were employed in a search for anomalous interactions. The results are combined with those from the four-lepton and two-photon decay channels to yield the most stringent constraints on anomalous Higgs boson couplings to date. The pure $CP$-odd scenario of the Higgs boson coupling to gluons is excluded at 2.4 standard deviations. The results are consistent with the standard model predictions.
Observed likelihood scan of $f_{a3}^{\mathrm{ggH}}$ (MELA method).
Expected likelihood scan of $f_{a3}^{\mathrm{ggH}}$ (MELA method).
Observed likelihood scan of $f_{a3}^{\mathrm{ggH}}$ ($\Delta\phi_{\mathrm{jj}}$ method).
Evidence is presented for the electroweak (EW) production of two jets (jj) in association with two Z bosons and constraints on anomalous quartic gauge couplings are set. The analysis is based on a data sample of proton-proton collisions at $\sqrt{s} = $ 13 TeV collected with the CMS detector in 2016-2018, and corresponding to an integrated luminosity of 137 fb$^{-1}$. The search is performed in the fully leptonic final state ZZ $\to$ $\ell\ell\ell'\ell'$, where $\ell,\ell' = $ e, $\mu$. The EW production of two jets in association with two Z bosons is measured with an observed (expected) significance of 4.0 (3.5) standard deviations. The cross sections for the EW production are measured in three fiducial volumes and the result is $\sigma_{\mathrm{EW}}$(pp $\to$ ZZjj $\to$ $\ell\ell\ell'\ell'$jj) = 0.33 $^{+0.11}_{-0.10}$ (stat) $^{+0.04}_{-0.03}$ (syst) fb in the most inclusive volume, in agreement with the standard model prediction of 0.275 $\pm$ 0.021 fb. Measurements of total cross sections for jj production in association with two Z bosons are also reported. Limits on anomalous quartic gauge couplings are derived in terms of the effective field theory operators T0, T1, T2, T8, and T9.
Data from paper Table 3. Measured and expected fiducial cross-sections in the ZZjj inclusive fiducial region.
Data from paper Table 3. Measured and expected fiducial cross-sections in the VBS-enriched loose fiducial region.
Data from paper Table 3. Measured and expected fiducial cross-sections in the VBS-enriched tight fiducial region.
A measurement of vector boson scattering and constraints on anomalous quartic gauge couplings from events with two Z bosons and two jets are presented. The analysis is based on a data sample of proton-proton collisions at sqrt(s) = 13 TeV collected with the CMS detector and corresponding to an integrated luminosity of 35.9 inverse femtobarns. The search is performed in the fully leptonic final state ZZ to lll'l', where l, l' = e, mu. The electroweak production of two Z bosons in association with two jets is measured with an observed (expected) significance of 2.7 (1.6) standard deviations. A fiducial cross section for the electroweak production is measured to be sigma[EW](pp -> ZZjj -> lll'l'jj) = 0.40 -0.16 +0.21 (stat) -0.09 +0.13 (syst) fb, which is consistent with the standard model prediction. Limits on anomalous quartic gauge couplings are determined in terms of the effective field theory operators T0, T1, T2, T8, and T9. This is the first measurement of vector boson scattering in the ZZ channel at the LHC.
Measured and expected fiducial cross-sections.
Measured and expected fiducial cross-sections.
Observed and expected exclusion limits for the aQGC parameters at 95% CL, without any form factors.
A measurement of electroweak-induced production of W gamma and two jets is performed, where the W boson decays leptonically. The data used in the analysis correspond to an integrated luminosity of 19.7 inverse femtobarns collected by the CMS experiment in sqrt(s) = 8 TeV proton-proton collisions produced at the LHC. Candidate events are selected with exactly one muon or electron, missing transverse momentum, one photon, and two jets with large rapidity separation. An excess over the hypothesis of the standard model without electroweak production of W gamma with two jets is observed with a significance of 2.7 standard deviations. The cross section measured in the fiducial region is 10.8 +/- 4.1 (stat) +/- 3.4 (syst) +/- 0.3 (lumi) fb, which is consistent with the standard model electroweak predictions. The total cross section for W gamma production in association with 2 jets in the same fiducial region is measured to be 23.2 +/- 4.3 (stat) +/- 1.7 (syst) +/- 0.6 (lumi) fb, which is consistent with the standard model prediction from the combination of electroweak- and quantum chromodynamics-induced processes. No deviations are observed from the standard model predictions and experimental limits on anomalous quartic gauge couplings f[M, 0-7] / Lambda^4, f[T, 0-2] / Lambda^4, and f[T, 5-7] / Lambda^4 are set at 95% confidence level.
Summary of the measured and predicted observables.
Observed and expected shape-based exclusion limits for the aQGC parameters at 95% CL, without any form factors.
Forum