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  1. Free, publicly-accessible full text available September 1, 2022
  2. Abstract The rate for Higgs ( $${\mathrm{H}} $$ H ) bosons production in association with either one ( $${\mathrm{t}} {\mathrm{H}} $$ t H ) or two ( $${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$ t t ¯ H ) top quarks is measured in final states containing multiple electrons, muons, or tau leptons decaying to hadrons and a neutrino, using proton–proton collisions recorded at a center-of-mass energy of $$13\,\text {TeV} $$ 13 TeV by the CMS experiment. The analyzed data correspond to an integrated luminosity of 137 $$\,\text {fb}^{-1}$$ fb - 1 . The analysis is aimed at events that contain $${\mathrm{H}} \rightarrowmore »{\mathrm{W}} {\mathrm{W}} $$ H → W W , $${\mathrm{H}} \rightarrow {\uptau } {\uptau } $$ H → τ τ , or $${\mathrm{H}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} $$ H → Z Z decays and each of the top quark(s) decays either to lepton+jets or all-jet channels. Sensitivity to signal is maximized by including ten signatures in the analysis, depending on the lepton multiplicity. The separation among $${\mathrm{t}} {\mathrm{H}} $$ t H , $${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$ t t ¯ H , and the backgrounds is enhanced through machine-learning techniques and matrix-element methods. The measured production rates for the $${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$ t t ¯ H and $${\mathrm{t}} {\mathrm{H}} $$ t H signals correspond to $$0.92 \pm 0.19\,\text {(stat)} ^{+0.17}_{-0.13}\,\text {(syst)} $$ 0.92 ± 0.19 (stat) - 0.13 + 0.17 (syst) and $$5.7 \pm 2.7\,\text {(stat)} \pm 3.0\,\text {(syst)} $$ 5.7 ± 2.7 (stat) ± 3.0 (syst) of their respective standard model (SM) expectations. The corresponding observed (expected) significance amounts to 4.7 (5.2) standard deviations for $${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$ t t ¯ H , and to 1.4 (0.3) for $${\mathrm{t}} {\mathrm{H}} $$ t H production. Assuming that the Higgs boson coupling to the tau lepton is equal in strength to its expectation in the SM, the coupling $$y_{{\mathrm{t}}}$$ y t of the Higgs boson to the top quark divided by its SM expectation, $$\kappa _{{\mathrm{t}}}=y_{{\mathrm{t}}}/y_{{\mathrm{t}}}^{\mathrm {SM}}$$ κ t = y t / y t SM , is constrained to be within $$-0.9< \kappa _{{\mathrm{t}}}< -0.7$$ - 0.9 < κ t < - 0.7 or $$0.7< \kappa _{{\mathrm{t}}}< 1.1$$ 0.7 < κ t < 1.1 , at 95% confidence level. This result is the most sensitive measurement of the $${\mathrm{t}} {{\overline{{{\mathrm{t}}}}}} {\mathrm{H}} $$ t t ¯ H production rate to date.« less
  3. A bstract Events containing one or more top quarks produced with additional prompt leptons are used to search for new physics within the framework of an effective field theory (EFT). The data correspond to an integrated luminosity of 41.5 fb − 1 of proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC, collected by the CMS experiment in 2017. The selected events are required to have either two leptons with the same charge or more than two leptons; jets, including identified bottom quark jets, are also required, and the selected events are divided into categories based onmore »the multiplicities of these objects. Sixteen dimension-six operators that can affect processes involving top quarks produced with additional charged leptons are considered in this analysis. Constructed to target EFT effects directly, the analysis applies a novel approach in which the observed yields are parameterized in terms of the Wilson coefficients (WCs) of the EFT operators. A simultaneous fit of the 16 WCs to the data is performed and two standard deviation confidence intervals for the WCs are extracted; the standard model expectations for the WC values are within these intervals for all of the WCs probed.« less