Differential cross-section measurements of the production of a top-antitop quark pair in association with a Z boson with the ATLAS detector

Watson, Harriet (2024) Differential cross-section measurements of the production of a top-antitop quark pair in association with a Z boson with the ATLAS detector. PhD thesis, University of Glasgow.

Abstract

This thesis describes differential cross-section measurements of the production of a top-antitop quark pair in association with a Z-boson (ttZ) in proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider (LHC) between 2015 and 2018 with a centre-of-mass-energy of √s = 13 TeV, corresponding to an integrated luminosity of 140 fb⁻¹. The analysis targets three- and four-lepton final states and aims to measure the differential cross-sections as precisely as possible. A profile likelihood unfolding method is used to extract differential cross-section measurements in a simultaneous fit in multiple orthogonal analysis regions. The differential cross-section measurements are presented as a function of a number of variables which probe the kinematics of the ttZ system. Both absolute and normalised differential cross-section measurements are performed at particle- and parton- level and are compared with theoretical predictions. Good agreement is seen between the data and predictions.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QB Astronomy; Q Science > QC Physics
• Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
• Funder's Name: Science and Technology Facilities Council (STFC)
• Supervisor's Name: Owen, Professor Mark
• Date of Award: 2024
• Depositing User: Theses Team
• Unique ID: glathesis:2024-84526
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 02 Sep 2024 08:47
• Last Modified: 02 Sep 2024 09:21
• Thesis DOI: 10.5525/gla.thesis.84526
• URI: https://theses.gla.ac.uk/id/eprint/84526

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