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  1. Free, publicly-accessible full text available November 1, 2024
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  4. Abstract Multijet events at large transverse momentum ( $$p_{\textrm{T}}$$ p T ) are measured at $$\sqrt{s}=13\,\text {TeV} $$ s = 13 TeV using data recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of $$36.3{\,\text {fb}^{-1}} $$ 36.3 fb - 1 . The multiplicity of jets with $$p_{\textrm{T}} >50\,\text {GeV} $$ p T > 50 GeV that are produced in association with a high- $$p_{\textrm{T}}$$ p T dijet system is measured in various ranges of the $$p_{\textrm{T}}$$ p T of the jet with the highest transverse momentum and as a function of the azimuthal angle difference $$\varDelta \phi _{1,2}$$ Δ ϕ 1 , 2 between the two highest $$p_{\textrm{T}}$$ p T jets in the dijet system. The differential production cross sections are measured as a function of the transverse momenta of the four highest $$p_{\textrm{T}}$$ p T 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. 
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    Free, publicly-accessible full text available August 1, 2024
  5. Free, publicly-accessible full text available August 1, 2024
  6. A<sc>bstract</sc>

    Results are presented from a search for CP violation in top quark pair production, using proton-proton collisions at a center-of-mass energy of 13 TeV. The data used for this analysis consist of final states with two charged leptons collected by the CMS experiment, and correspond to an integrated luminosity of 35.9 fb1. The search uses two observables,$$ \mathcal{O} $$O1and$$ \mathcal{O} $$O3, which are Lorentz scalars. The observable$$ \mathcal{O} $$O1is constructed from the four-momenta of the charged leptons and the reconstructed top quarks, while$$ \mathcal{O} $$O3consists of the four-momenta of the charged leptons and the b quarks originating from the top quarks. Asymmetries in these observables are sensitive to CP violation, and their measurement is used to determine the chromoelectric dipole moment of the top quark. The results are consistent with the expectation from the standard model.

     
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    Free, publicly-accessible full text available July 1, 2024
  7. Free, publicly-accessible full text available July 1, 2024
  8. Abstract

    The double differential cross sections of the Drell–Yan lepton pair ($$\ell ^+\ell ^-$$+-, dielectron or dimuon) production are measured as functions of the invariant mass$$m_{\ell \ell }$$m, transverse momentum$$p_{\textrm{T}} (\ell \ell )$$pT(), and$$\varphi ^{*}_{\eta }$$φη. The$$\varphi ^{*}_{\eta }$$φηobservable, derived from angular measurements of the leptons and highly correlated with$$p_{\textrm{T}} (\ell \ell )$$pT(), is used to probe the low-$$p_{\textrm{T}} (\ell \ell )$$pT()region in a complementary way. Dilepton masses up to 1$$\,\text {Te\hspace{-.08em}V}$$TeVare 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$$m_{\ell \ell }$$mranges 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-1of 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.

     
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    Free, publicly-accessible full text available July 1, 2024
  9. Free, publicly-accessible full text available July 1, 2024
  10. A bstract A combination of measurements of the inclusive top-quark pair production cross-section performed by ATLAS and CMS in proton–proton collisions at centre-of-mass energies of 7 and 8 TeV at the LHC is presented. The cross-sections are obtained using top-quark pair decays with an opposite-charge electron–muon pair in the final state and with data corresponding to an integrated luminosity of about 5 fb − 1 at $$ \sqrt{s} $$ s = 7 TeV and about 20 fb − 1 at $$ \sqrt{s} $$ s = 8 TeV for each experiment. The combined cross-sections are determined to be 178 . 5 ± 4 . 7 pb at $$ \sqrt{s} $$ s = 7 TeV and $$ {243.3}_{-5.9}^{+6.0} $$ 243.3 − 5.9 + 6.0 pb at $$ \sqrt{s} $$ s = 8 TeV with a correlation of 0.41, using a reference top-quark mass value of 172.5 GeV. The ratio of the combined cross-sections is determined to be R 8 / 7 = 1 . 363 ± 0 . 032. The combined measured cross-sections and their ratio agree well with theory calculations using several parton distribution function (PDF) sets. The values of the top-quark pole mass (with the strong coupling fixed at 0.118) and the strong coupling (with the top-quark pole mass fixed at 172.5 GeV) are extracted from the combined results by fitting a next-to-next-to-leading-order plus next-to-next-to-leading-log QCD prediction to the measurements. Using a version of the NNPDF3.1 PDF set containing no top-quark measurements, the results obtained are $$ {m}_t^{\textrm{pole}}={173.4}_{-2.0}^{+1.8} $$ m t pole = 173.4 − 2.0 + 1.8 GeV and $$ {\alpha}_{\textrm{s}}\left({m}_Z\right)={0.1170}_{-0.0018}^{+0.0021} $$ α s m Z = 0.1170 − 0.0018 + 0.0021 . 
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    Free, publicly-accessible full text available July 1, 2024