Lyons, Harry
(2022)
Measurement of Z-boson production
and luminosity monitoring using
5.02 TeV and 13 TeV ATLAS Run-2 pp
collision data.
PhD thesis, University of Liverpool.
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200964907_Mar2022.pdf - Author Accepted Manuscript Download (20MB) | Preview |
Abstract
Two analyses involving Drell-Yan production using ATLAS Run-2 pp collision data are presented. First, the monitoring of luminosity at 60 second granularity using the Z-counting method is presented. This involves the selection of Z→ee and Z→µµ events combined with data-driven efficiency calculations and pileup dependent corrections from Monte Carlo. Comparisons of luminosity estimates are performed using the full Run-2 dataset from 2015-2018, where internal consistency is shown between of Z→ee and Z→µµ methods and year-dependent trends of size 1% are shown between Z-counting and the baseline ATLAS luminosity measurement. An additional study is performed to quantify statistical bias in the Z-counting methodology, which is observed to be negligible for most Run-2 conditions but can be as large as 2% when the instantaneous luminosity is low. Second, the measurement of a triple-differential Drell-Yan cross-section in mll, yll and cos(θCS) is presented. These measurements use the special low-µ runs from 2017 and 2018, constituting 256.8 pb-1 at √s = 5.02 TeV and 335.2 pb-1 at √s = 13 TeV. This includes the derivation of muon trigger efficiency scale factors, the estimation of multijet background contribution and the implementation of an unfolding procedure. The unfolded differential cross-sections are shown to be statistically limited in most analysis bins, and the inclusive fiducial cross-sections are shown to be limited by the luminosity uncertainty in the central-mass region.
| Item Type: | Thesis (PhD) |
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| Divisions: | Faculty of Science and Engineering > School of Physical Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 10 Nov 2022 16:19 |
| Last Modified: | 18 Jan 2023 20:36 |
| DOI: | 10.17638/03165542 |
| Supervisors: |
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| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3165542 |
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