Top quark event modelling and generators in the CMS experiment at the LHC

TL;DR

This paper evaluates the accuracy of advanced theoretical models and event generators in simulating top quark pair production and associated activity in CMS data at 8 and 13 TeV, including beyond NLO predictions.

Contribution

It provides a comprehensive comparison of next-to-leading order and beyond NLO QCD predictions with experimental data from CMS for top quark events.

Findings

NLO QCD predictions agree well with data for top pair production.

Predictions of underlying event activity match observed distributions.

Beyond NLO predictions offer improved modeling of top quark events.

Abstract

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.