Speaker
Description
Measurements of the inclusive and differential top quark pair production cross section via the strong force at 7 TeV, 8 TeV and 13 TeV are presented, performed using CMS data collected in 2011, 2012 and 2015. The total cross section is measured in the lepton+jets, dilepton and fully hadronic channels, including the tau-dilepton and tau+jets modes. Indirect constraints on both the top quark mass and $\alpha_{s}$ are obtained through their relation to the inclusive cross section. First measurements of top quark pair production with additional $b$-quarks in the final state are also presented. Differential cross sections are measured and are given as functions of various kinematic observables, including the transverse momentum and rapidity of the (anti)top quark and the top-antitop system and the jets and leptons of the event final state. Multiplicity and kinematic distributions of the jets produced in addition to the top pair are also investigated. The results are combined and confronted with precise theory calculations.
We also present result on top quark event modeling. State-of-the-art theoretical predictions accurate to next-to-leading order QCD interfaced with Pythia8 and Herwig++ event generators are tested by comparing the unfolded $t\bar{t}$ differential data collected with the CMS detector at 8 TeV. These predictions are also compared with the underlying event activity distributions in $t\bar{t}$ events using CMS proton-proton data collected in 2015 at a center of mass energy of 13 TeV.
