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Observation of tt¯ production in the lepton+jets and dilepton channels in p+Pb collisions at √sNN = 8.16 TeV with the ATLAS detector ATLAS Collaboration

Abstract

This paper reports the observation of top-quark pair production in proton-lead collisions in the ATLAS experiment at the Large Hadron Collider. The measurement is performed using 165 nb−1 of p+Pb data collected at √ sNN = 8.16 TeV in 2016. Events are categorised in two analysis channels, consisting of either events with exactly one lepton (electron or muon) and at least four jets, or events with two opposite-charge leptons and at least two jets. In both channels at least one b-tagged jet is also required. Top-quark pair production is observed with a signifcance over fve standard deviations in each channel. The top-quark pair production cross-section is measured to be σtt¯= 58.1±2.0 (stat.) +4.8 −4.4 (syst.) nb, with a total uncertainty of 9%. In addition, the nuclear modifcation factor is measured to be RpA = 1.090 ± 0.039 (stat.) +0.094 −0.087 (syst.). The measurements are found to be in good agreement with theory predictions involving nuclear parton distribution functions.

Item Metadata

Title
Observation of tt¯ production in the lepton+jets and dilepton channels in p+Pb collisions at √sNN = 8.16 TeV with the ATLAS detector
Creator
ATLAS Collaboration
Publisher
Springer Berlin Heidelberg
Date Issued
2024-11-19
Description
This paper reports the observation of top-quark pair production in proton-lead collisions in the ATLAS experiment at the Large Hadron Collider. The measurement is performed using 165 nb−1 of p+Pb data collected at √ sNN = 8.16 TeV in 2016. Events are categorised in two analysis channels, consisting of either events with exactly one lepton (electron or muon) and at least four jets, or events with two opposite-charge leptons and at least two jets. In both channels at least one b-tagged jet is also required. Top-quark pair production is observed with a signifcance over fve standard deviations in each channel. The top-quark pair production cross-section is measured to be σtt¯= 58.1±2.0 (stat.) +4.8 −4.4 (syst.) nb, with a total uncertainty of 9%. In addition, the nuclear modifcation factor is measured to be RpA = 1.090 ± 0.039 (stat.) +0.094 −0.087 (syst.). The measurements are found to be in good agreement with theory predictions involving nuclear parton distribution functions.
Subject
Heavy Ion Experiments; Top Physics
Genre
Article
Type
Text
Language
eng
Date Available
2025-07-15
Provider
Vancouver : University of British Columbia Library
Rights
Attribution 4.0 International (CC BY 4.0)
DOI
10.14288/1.0449395
URI
http://hdl.handle.net/2429/91625
Affiliation
Science, Faculty of; TRIUMF; Non UBC; Physics and Astronomy, Department of
Citation
Journal of High Energy Physics. 2024 Nov 19;2024(11):101
Publisher DOI
10.1007/JHEP11(2024)101
Peer Review Status
Reviewed
Scholarly Level
Faculty; Researcher
Copyright Holder
The Author(s)
Rights URI
http://creativecommons.org/licenses/by/4.0/
Aggregated Source Repository
DSpace

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Rights

Attribution 4.0 International (CC BY 4.0)