# Jet energy scale measurements and their systematic uncertainties in proton-proton collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

## TL;DR

This paper reports precise measurements of the jet energy scale and systematic uncertainties in proton-proton collisions at 13 TeV using the ATLAS detector, employing calibration techniques and in situ methods to achieve uncertainties below 1% in central regions.

## Contribution

It introduces a comprehensive calibration and uncertainty estimation method for jet energy measurements at the LHC, improving precision over previous approaches.

## Key findings

- Jet energy scale uncertainty less than 1% in central region for 100-500 GeV jets.
- Uncertainty of about 4.5% for low-$p_{T}$ jets at 20 GeV.
- Forward jet calibration uncertainty reaches about 2% at high pseudorapidities.

## Abstract

Jet energy scale measurements and their systematic uncertainties are reported for jets measured with the ATLAS detector using proton-proton collision data with a center-of-mass energy of $\sqrt{s} = 13$ TeV, corresponding to an integrated luminosity of 3.2 fb$^{-1}$ collected during 2015 at the LHC. Jets are reconstructed from energy deposits forming topological clusters of calorimeter cells, using the anti-$k_{t}$ algorithm with radius parameter $R = 0.4$. Jets are calibrated with a series of simulation-based corrections and in situ techniques. In situ techniques exploit the transverse momentum balance between a jet and a reference object such as a photon, $Z$ boson, or multijet system for jets with $20 < p_{T} < 2000$ GeV and pseudorapidities of $|\eta|<4.5$, using both data and simulation. An uncertainty in the jet energy scale of less than 1% is found in the central calorimeter region ($|\eta| < 1.2$) for jets with $100 < p_{T} < 500$ GeV. An uncertainty of about 4.5% is found for low-$p_{T}$ jets with $p_{T} = 20$ GeV in the central region, dominated by uncertainties in the corrections for multiple proton-proton interactions. The calibration of forward jets ($|\eta| > 0.8$) is derived from dijet $p_{T}$ balance measurements. For jets of $p_{T} = 80$ GeV, the additional uncertainty for the forward jet calibration reaches its largest value of about 2% in the range $|\eta| > 3.5$ and in a narrow slice of $2.2 < |\eta| < 2.4$.