# Top Quark Modelling and Tuning at CMS

## TL;DR

This paper summarizes recent CMS measurements at 13 TeV that improve top quark pair production modeling, including underlying event studies, jet substructure analysis, and new PYTHIA 8 tunes evaluated against data.

## Contribution

It introduces new tunes for PYTHIA 8 and assesses their performance in modeling top quark pair production at the LHC.

## Key findings

- Improved understanding of top quark pair production modeling.
- Development of new PYTHIA 8 tunes.
- Validation of tunes with CMS data.

## Abstract

Recent measurements dedicated to improving the understanding of modelling top quark pair (${\text{t}\overline{\text{t}}}$) production at the LHC are summarised. These measurements, performed with proton-proton collision data collected by the CMS detector at $\sqrt{s}=$ 13 TeV, probe the underlying event in ${\text{t}\overline{\text{t}}}$ events, and use the abundance of jets in ${\text{t}\overline{\text{t}}}$ events to study the substructure of jets. A new set of tunes for PYTHIA 8, and their performance with ${\text{t}\overline{\text{t}}}$ data, are also discussed.