# Top-quark pair production in association with a W or Z boson with the ATLAS experiment

## TL;DR

This paper reports measurements of the production cross sections of top-quark pairs with associated W or Z bosons using ATLAS data, confirming consistency with Standard Model predictions.

## Contribution

First simultaneous measurement of t-tbar-Z and t-tbar-W cross sections at 13 TeV with detailed statistical and systematic analysis.

## Key findings

- Measured cross sections are consistent with Standard Model.
- Quantified statistical and systematic uncertainties.
- Provided precise cross section values for t-tbar-Z and t-tbar-W processes.

## Abstract

The cross section of the $t\bar{t}Z$ and $t\bar{t}W$ processes are measured in a simultaneous fit using 36.1 $\text{fb}^{-1}$ of proton-proton collisions at a centre of mass energy of $\sqrt{s}=13$ TeV recorded by the ATLAS detector at the LHC. The result is found to be $\sigma_{t\bar{t}Z} = 0.95 \pm 0.08 \text{ (stat.)} \pm 0.10 \text{ (syst.)}\,\text{pb}$ and $\sigma_{t\bar{t}W} = 0.87 \pm 0.13 \text{ (stat.)} \pm 0.14 \text{ (syst.)}\,\text{pb}$ and compatible with the Standard Model.