Differential and double-differential cross sections for the production of top quark pairs in proton-proton collisions at 13 TeV are measured as a function of jet multiplicity and of kinematic variables of the top quarks and the top quark-antiquark system. This analysis is based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurements are performed in the lepton+jets decay channels with a single muon or electron in the final state. The differential cross sections are presented at particle level, within a phase space close to the experimental acceptance, and at parton level in the full phase space. The results are compared to several standard model predictions.
Absolute cross section at particle level.
Covariance matrix of absolute cross section at particle level.
Absolute cross section at particle level.
Constraints on the Wilson coefficients (WCs) corresponding to dimension-six operators of the standard model effective field theory (SMEFT) are determined from a simultaneous fit to seven sets of CMS measurements probing Higgs boson, electroweak vector boson, top quark, and multi-jet production. The measurements of the electroweak precision observables at LEP and SLC are also included and provide complementary constraints to those from CMS. The CMS measurements, using $36$-$138\,\mathrm{fb}^{-1}$ of LHC proton-proton collision data at $\sqrt{s}=13\,\mathrm{TeV}$, are chosen to provide sensitivity to a broad set of operators, for which consistent SMEFT predictions can be derived. These are primarily measurements of differential cross sections or, in the case of Higgs boson production, simplified template cross sections, which are subsequently parametrized in the WCs. Measurements targeting $\mathrm{t\bar{t}X}$ production model the SMEFT effects directly in the reconstructed observables. Individual constraints on 64 WCs, and constraints on 42 linear combinations of WCs, are obtained. In the case of the linear combinations, the 42 parameters are varied simultaneously.
Expected and observed 95% CL limits on linear combinations of Wilson coefficients from the hybrid fit with the full set of input measurements.
Expected and observed individual 95% CL limits on Wilson coefficients from the hybrid fit with the full set of input measurements.
Rotation matrix obtained by performing the PCA on the Hessian matrix of the full set of measurements, including the t(t)X analysis.
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