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A measurement of the jet mass distribution in hadronic decays of Lorentz-boosted top quarks is presented. The measurement is performed in the lepton + jets channel of top quark pair production ( ) events, where the lepton is an electron or muon. The products of the hadronic top quark decay are reconstructed using a single large-radius jet with transverse momentum greater than 400 . The data were collected with the CMS detector at the LHC in proton-proton collisions and correspond to an integrated luminosity of 138 . The differential production cross section as a function of the jet mass is unfolded to the particle level and is used to extract the top quark mass. The jet mass scale is calibrated using the hadronic W boson decay within the large-radius jet. The uncertainties in the modelling of the final state radiation are reduced by studying angular correlations in the jet substructure. These developments lead to a significant increase in precision, and a top quark mass of .

The double differential cross sections of the Drell–Yan lepton pair ( $$\\ell ^+\\ell ^-$$ ℓ + ℓ - , dielectron or dimuon) production are measured as functions of the invariant mass $$m_{\\ell \\ell }$$ m ℓ ℓ , transverse momentum $$p_{\\textrm{T}} (\\ell \\ell )$$ p T ( ℓ ℓ ) , and $$\\varphi ^{*}_{\\eta }$$ φ η ∗ . The $$\\varphi ^{*}_{\\eta }$$ φ η ∗ observable, derived from angular measurements of the leptons and highly correlated with $$p_{\\textrm{T}} (\\ell \\ell )$$ p T ( ℓ ℓ ) , is used to probe the low- $$p_{\\textrm{T}} (\\ell \\ell )$$ p T ( ℓ ℓ ) region in a complementary way. Dilepton masses up to 1 $$\\,\\text {Te\\hspace{-.08em}V}$$ Te V are investigated. Additionally, a measurement is performed requiring at least one jet in the final state. To benefit from partial cancellation of the systematic uncertainty, the ratios of the differential cross sections for various $$m_{\\ell \\ell }$$ m ℓ ℓ ranges to those in the Z mass peak interval are presented. The collected data correspond to an integrated luminosity of 36.3 $$\\,\\text {fb}^{-1}$$ fb - 1 of proton–proton collisions recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 $$\\,\\text {Te\\hspace{-.08em}V}$$ Te V . Measurements are compared with predictions based on perturbative quantum chromodynamics, including soft-gluon resummation.

The first search for nonresonant production of Higgs boson pairs (HH) with one H decaying into four leptons and the other into a pair of b quarks is presented, using proton-proton collisions recorded at a center-of-mass energy of$$ \\sqrt{s} $$s = 13 TeV by the CMS experiment. The analyzed data correspond to an integrated luminosity of 138 fb − 1 . A 95% confidence level upper limit of 32.4 is set on the signal strength modifier μ , defined as the ratio of the observed HH production rate in the$$ \\textrm{HH}\\to {\\textrm{ZZ}}^{\\ast}\\textrm{b}\\overline{\\textrm{b}}\\to 4\\ell \\textrm{b}\\overline{\\textrm{b}} $$HH → ZZ ∗ b b ¯ → 4 ℓ b b ¯ decay channel to the standard model (SM) expectation. Possible modifications of the H trilinear coupling λ HHH with respect to the SM value are investigated. The coupling modifier κ λ , defined as λ HHH divided by its SM prediction, is constrained to be within the observed (expected) range − 8 . 8 ( − 9 . 8) < κ λ < 13 . 4 (15 . 0) at 95% confidence level.

The double differential cross sections of the Drell-Yan lepton pair ( , dielectron or dimuon) production are measured as functions of the invariant mass , transverse momentum , and . The observable, derived from angular measurements of the leptons and highly correlated with , is used to probe the low- region in a complementary way. Dilepton masses up to 1 are investigated. Additionally, a measurement is performed requiring at least one jet in the final state. To benefit from partial cancellation of the systematic uncertainty, the ratios of the differential cross sections for various ranges to those in the Z mass peak interval are presented. The collected data correspond to an integrated luminosity of 36.3 of proton-proton collisions recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 . Measurements are compared with predictions based on perturbative quantum chromodynamics, including soft-gluon resummation.

The double differential cross sections of the Drell–Yan lepton pair ( $$\\ell ^+\\ell ^-$$ ℓ+ℓ-, dielectron or dimuon) production are measured as functions of the invariant mass $$m_{\\ell \\ell }$$ mℓℓ, transverse momentum $$p_{\\textrm{T}} (\\ell \\ell )$$ pT(ℓℓ), and $$\\varphi ^{*}_{\\eta }$$ φη∗. The $$\\varphi ^{*}_{\\eta }$$ φη∗ observable, derived from angular measurements of the leptons and highly correlated with $$p_{\\textrm{T}} (\\ell \\ell )$$ pT(ℓℓ), is used to probe the low- $$p_{\\textrm{T}} (\\ell \\ell )$$ pT(ℓℓ) region in a complementary way. Dilepton masses up to 1 $$\\,\\text {Te\\hspace{-.08em}V}$$ TeV are investigated. Additionally, a measurement is performed requiring at least one jet in the final state. To benefit from partial cancellation of the systematic uncertainty, the ratios of the differential cross sections for various $$m_{\\ell \\ell }$$ mℓℓ ranges to those in the Z mass peak interval are presented. The collected data correspond to an integrated luminosity of 36.3 $$\\,\\text {fb}^{-1}$$ fb-1 of proton–proton collisions recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 $$\\,\\text {Te\\hspace{-.08em}V}$$ TeV. Measurements are compared with predictions based on perturbative quantum chromodynamics, including soft-gluon resummation.

Measurements of Higgs boson production, where the Higgs boson decays into a pair of $$\\uptau $$ τ leptons, are presented, using a sample of proton-proton collisions collected with the CMS experiment at a center-of-mass energy of \"Equation missing\" , corresponding to an integrated luminosity of 138 $$\\,\\text {fb}^{-1}$$ fb - 1 . Three analyses are presented. Two are targeting Higgs boson production via gluon fusion and vector boson fusion: a neural network based analysis and an analysis based on an event categorization optimized on the ratio of signal over background events. These are complemented by an analysis targeting vector boson associated Higgs boson production. Results are presented in the form of signal strengths relative to the standard model predictions and products of cross sections and branching fraction to $$\\uptau $$ τ leptons, in up to 16 different kinematic regions. For the simultaneous measurements of the neural network based analysis and the analysis targeting vector boson associated Higgs boson production signal strengths are found to be $$0.82\\pm 0.11$$ 0.82 ± 0.11 for inclusive Higgs boson production, $$0.67\\pm 0.19$$ 0.67 ± 0.19 ( $$0.81\\pm 0.17$$ 0.81 ± 0.17 ) for the production mainly via gluon fusion (vector boson fusion), and $$1.79\\pm 0.45$$ 1.79 ± 0.45 for vector boson associated Higgs boson production.

Multijet events at large transverse momentum ( $$p_{\\textrm{T}}$$ pT) are measured at $$\\sqrt{s}=13\\,\\text {Te\\hspace{-.08em}V} $$ s=13TeV using data recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of $$36.3{\\,\\text {fb}^{-1}} $$ 36.3fb-1. The multiplicity of jets with $$p_{\\textrm{T}} >50\\,\\text {Ge\\hspace{-.08em}V} $$ pT>50GeV that are produced in association with a high- $$p_{\\textrm{T}}$$ pT dijet system is measured in various ranges of the $$p_{\\textrm{T}}$$ pT of the jet with the highest transverse momentum and as a function of the azimuthal angle difference $$\\varDelta \\phi _{1,2}$$ Δϕ1,2 between the two highest $$p_{\\textrm{T}}$$ pT jets in the dijet system. The differential production cross sections are measured as a function of the transverse momenta of the four highest $$p_{\\textrm{T}}$$ pT jets. The measurements are compared with leading and next-to-leading order matrix element calculations supplemented with simulations of parton shower, hadronization, and multiparton interactions. In addition, the measurements are compared with next-to-leading order matrix element calculations combined with transverse-momentum dependent parton densities and transverse-momentum dependent parton shower.

Production cross sections of the standard model Higgs boson decaying to a pair of W bosons are measured in proton-proton collisions at a center-of-mass energy of 13 . The analysis targets Higgs bosons produced via gluon fusion, vector boson fusion, and in association with a W or Z boson. Candidate events are required to have at least two charged leptons and moderate missing transverse momentum, targeting events with at least one leptonically decaying W boson originating from the Higgs boson. Results are presented in the form of inclusive and differential cross sections in the simplified template cross section framework, as well as couplings of the Higgs boson to vector bosons and fermions. The data set collected by the CMS detector during 2016-2018 is used, corresponding to an integrated luminosity of 138 . The signal strength modifier , defined as the ratio of the observed production rate in a given decay channel to the standard model expectation, is measured to be . All results are found to be compatible with the standard model within the uncertainties.

The mass of the top quark is measured in 36.3 of LHC proton-proton collision data collected with the CMS detector at . The measurement uses a sample of top quark pair candidate events containing one isolated electron or muon and at least four jets in the final state. For each event, the mass is reconstructed from a kinematic fit of the decay products to a top quark pair hypothesis. A profile likelihood method is applied using up to four observables per event to extract the top quark mass. The top quark mass is measured to be . This approach significantly improves the precision over previous measurements.