State-of-the-art theoretical predictions accurate to next-to-leading order QCD interfaced with { \sc pythia} and { \sc herwig} are tested by comparing the unfolded $t\bar{ t}$ differential data collected with the CMS detector at 8 TeV and 13 TeV. These predictions are also compared with the measurements of underlying event activity distributions accompanying ${ \rm t\bar{ t}}$ events. Furthermore, predictions of beyond NLO accuracy in QCD are compared with the data.
Categories: hep-ex