# Measurements of the production cross section of a $Z$ boson in association with jets in pp collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

## TL;DR

This paper reports precise measurements of Z boson production with jets at 13 TeV, comparing results with various theoretical models, and finds good agreement especially with advanced NLO and NNLO predictions.

## Contribution

First detailed measurement of Z+jets cross sections at 13 TeV with extensive comparison to multiple theoretical predictions.

## Key findings

- Good agreement with NLO and NNLO models
- Measurements extend up to seven jets
- Data constrains theoretical modeling of Z+jets production

## Abstract

Measurements of the production cross section of a $Z$ boson in association with jets in proton-proton collisions at $\sqrt{s} = 13$ TeV are presented, using data corresponding to an integrated luminosity of 3.16 fb$^{-1}$ collected by the ATLAS experiment at the CERN Large Hadron Collider in 2015. Inclusive and differential cross sections are measured for events containing a $Z$ boson decaying to electrons or muons and produced in association with up to seven jets with $p_T > 30$ GeV and $|y| <2.5$. Predictions from different Monte Carlo generators based on leading-order and next-to-leading-order matrix elements for up to two additional partons interfaced with parton shower and fixed-order predictions at next-to-leading order and next-to-next-to-leading order are compared with the measured cross sections. Good agreement within the uncertainties is observed for most of the modelled quantities, in particular with the generators which use next-to-leading-order matrix elements and the more recent next-to-next-to-leading-order fixed-order predictions.