Book/Report/Dissertation / PhD Thesis

PUBDB-2017-13967

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Measurements of $\mathrm{W^±}$ and top-quark pair to Z-boson cross-section ratios at $\mathrm{\sqrt{s}}$ = 13, 8, 7 TeV with the ATLAS detector

Trofymov, A. (Corresponding author)DESY* ; Glazov, A. (Thesis advisor)DESY* ; Schleper, P. (Thesis advisor)Extern*

2018
Verlag Deutsches Elektronen-Synchrotron Hamburg

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Please use a persistent id in citations: doi:10.3204/PUBDB-2017-13967

Report No.: DESY-THESIS-2018-001

Abstract: Measurements of the $Z \rightarrow \ell^+\ell^-$ production cross sections, where ` = e; , in protonprotoncollisions at ps = 13 TeV are presented using two sets of data recorded by the ATLAS experiment at the Large Hadron Collider. The data sets correspond to a totalintegrated luminosity of 81 pb$^{-1}$ and 3:2 fb$^{-1}$ collected in 2015 using the 50 ns and25 ns bunch spacing congurations, respectively. The cross section obtained with 50 nsconguration is used for W to Z cross-section ratio measurement. The W+ to W- boson production cross-section ratio is also measured. The ratios of measured ducial crosss ections for electron and muon decay channels of the W and Z boson are evaluated andcompared to the Standard Model expectations of the lepton universality.Ratio of top-quark pair to Z-boson production cross section is measured at ps = 13 TeVusing 25 ns bunch spacing data. Similar ratios are obtained at ps = 8 TeV and 7 TeVusing the published ATLAS results corrected to a common phase space. Single ratios, ata given ps for the two processes and at dierent ps for each process, as well as doubleratios of the two processes at dierent ps, are evaluated. The results are compared to calculationsperformed at next-to-next-to-leading-order accuracy using recent sets of partondistribution functions. The data used for tt to Z-boson cross section ratios demonstratesignicant power to constrain the gluon distribution function for the Bjorken-x valuesnear 0.1 and the light-quark sea for x < 0:02.

Note: Dissertation, Universität Hamburg, 2017

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Contributing Institute(s):

1. LHC/ATLAS Experiment (ATLAS)

Research Program(s):

1. 611 - Fundamental Particles and Forces (POF3-611) (POF3-611)

Experiment(s):

1. LHC: ATLAS

Appears in the scientific report 2017

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Database coverage:

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