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A precise measurement of the Z boson cross-section and a test of the Standard Model using the LHCb detector
Measurements of production cross-sections for $Z$ bosons that decay to muons are presented in this thesis. The data used to perform the measurements were recorded by the LHCb detector during $pp$ collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of approx...
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Lenguaje: | eng |
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2015
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Acceso en línea: | http://cds.cern.ch/record/2109584 |
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author | Wallace, Ronan James |
author_facet | Wallace, Ronan James |
author_sort | Wallace, Ronan James |
collection | CERN |
description | Measurements of production cross-sections for $Z$ bosons that decay to muons are presented in this thesis. The data used to perform the measurements were recorded by the LHCb detector during $pp$ collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of approximately 1.0 and 2.0 fb$^{-1}$. The cross-sections are measured for muons in the pseudorapidity range $2.0 <\eta < 4.5$ with transverse momenta $p_{T} > 20$ GeV/c. The dimuon mass is restricted to $60 < M_{\mu^{+}\mu^{-}} < 120$ GeV/c$^{2}$. Total cross-sections are determined with a precision of approximately 2$\%$. Cross-sections are also measured as functions of kinematic variables relating to the $Z$ boson. Ratios of production cross-sections of electroweak bosons are presented using measurements of $W$ boson production. A precise test of the Standard Model is provided by the measurement of the ratio $$\frac{\sigma_{W^{+}\rightarrow\mu^{+}\nu_{\mu}} + \sigma_{W^{-}\rightarrow\mu^{-}\bar{\nu}_{\mu}}}{\sigma_{Z\rightarrow\mu^{+}\mu^{-}}} $$ where the uncertainty due to luminosity, and other correlated uncertainties, cancels. This cancellation allows the cross-section ratios to be measured with an overall precision below 1$\%$. Measurements of electroweak boson cross-section ratios as functions of muon $\eta$ are presented for the first time. Measurements of cross-section ratios and ratios-of-ratios of cross-sections at different centre-of-mass energies are also presented for the first time. Cross-section ratios at different centre-of-mass energies are determined with a precision of approximately 1.6$\%$. Ratios-of-ratios of cross-sections are measured with an overall precision below 1$\%$. All measurements are consistent with the predictions of the SM. It is expected that the data presented here will help place significant constraints on the form of proton PDFs. |
id | cern-2109584 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 2015 |
record_format | invenio |
spelling | cern-21095842019-09-30T06:29:59Zhttp://cds.cern.ch/record/2109584engWallace, Ronan JamesA precise measurement of the Z boson cross-section and a test of the Standard Model using the LHCb detectorParticle Physics - ExperimentMeasurements of production cross-sections for $Z$ bosons that decay to muons are presented in this thesis. The data used to perform the measurements were recorded by the LHCb detector during $pp$ collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of approximately 1.0 and 2.0 fb$^{-1}$. The cross-sections are measured for muons in the pseudorapidity range $2.0 <\eta < 4.5$ with transverse momenta $p_{T} > 20$ GeV/c. The dimuon mass is restricted to $60 < M_{\mu^{+}\mu^{-}} < 120$ GeV/c$^{2}$. Total cross-sections are determined with a precision of approximately 2$\%$. Cross-sections are also measured as functions of kinematic variables relating to the $Z$ boson. Ratios of production cross-sections of electroweak bosons are presented using measurements of $W$ boson production. A precise test of the Standard Model is provided by the measurement of the ratio $$\frac{\sigma_{W^{+}\rightarrow\mu^{+}\nu_{\mu}} + \sigma_{W^{-}\rightarrow\mu^{-}\bar{\nu}_{\mu}}}{\sigma_{Z\rightarrow\mu^{+}\mu^{-}}} $$ where the uncertainty due to luminosity, and other correlated uncertainties, cancels. This cancellation allows the cross-section ratios to be measured with an overall precision below 1$\%$. Measurements of electroweak boson cross-section ratios as functions of muon $\eta$ are presented for the first time. Measurements of cross-section ratios and ratios-of-ratios of cross-sections at different centre-of-mass energies are also presented for the first time. Cross-section ratios at different centre-of-mass energies are determined with a precision of approximately 1.6$\%$. Ratios-of-ratios of cross-sections are measured with an overall precision below 1$\%$. All measurements are consistent with the predictions of the SM. It is expected that the data presented here will help place significant constraints on the form of proton PDFs.CERN-THESIS-2015-223oai:cds.cern.ch:21095842015-11-30T13:37:40Z |
spellingShingle | Particle Physics - Experiment Wallace, Ronan James A precise measurement of the Z boson cross-section and a test of the Standard Model using the LHCb detector |
title | A precise measurement of the Z boson cross-section and a test of the Standard Model using the LHCb detector |
title_full | A precise measurement of the Z boson cross-section and a test of the Standard Model using the LHCb detector |
title_fullStr | A precise measurement of the Z boson cross-section and a test of the Standard Model using the LHCb detector |
title_full_unstemmed | A precise measurement of the Z boson cross-section and a test of the Standard Model using the LHCb detector |
title_short | A precise measurement of the Z boson cross-section and a test of the Standard Model using the LHCb detector |
title_sort | precise measurement of the z boson cross-section and a test of the standard model using the lhcb detector |
topic | Particle Physics - Experiment |
url | http://cds.cern.ch/record/2109584 |
work_keys_str_mv | AT wallaceronanjames aprecisemeasurementofthezbosoncrosssectionandatestofthestandardmodelusingthelhcbdetector AT wallaceronanjames precisemeasurementofthezbosoncrosssectionandatestofthestandardmodelusingthelhcbdetector |