Suppression of the fake lepton background in same-sign W-boson scattering with the ATLAS experiment

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dc.contributor.advisorHamilton, Andrewen_ZA
dc.contributor.advisorYacoob, Sahalen_ZA
dc.contributor.authorMcConnell, Lucas Henryen_ZA
dc.date.accessioned2018-02-05T13:05:50Z
dc.date.available2018-02-05T13:05:50Z
dc.date.issued2017en_ZA
dc.description.abstractSame-sign W-boson scattering is a rare Standard Model process that is useful for probing the nature of electroweak symmetry breaking and the Higgs mechanism. Analysis is currently underway to measure the cross-section to a significance of 5σ or higher using √s = 13 TeV data from the ATLAS detector's Run 2. The two scattered W-bosons decay leptonically leaving a distinctive experimental signature of two same-sign leptons, two forward jets, and missing transverse energy carried away by two neutrinos. Non-prompt leptons are defined as leptons coming from the decay of hadrons. Such leptons, together with jets misreconstructed as leptons, contribute to the background processes in same-sign W-boson scattering; making up the so-called fake lepton background. In this thesis the fake lepton background is suppressed using two strategies: 1) implementing an optimised veto on events found to contain a b-jet; and 2) optimising the isolation requirements set on signal lepton candidates using the cumulative significance quantity. The approach using the cumulative significance is then extended to optimise additional analysis cuts on the lepton invariant mass mₗₗ, jet invariant mass mⱼⱼ , and the jet separation rapidity Δyⱼⱼ.en_ZA
dc.identifier.apacitationMcConnell, L. H. (2017). <i>Suppression of the fake lepton background in same-sign W-boson scattering with the ATLAS experiment</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Physics. Retrieved from http://hdl.handle.net/11427/27311en_ZA
dc.identifier.chicagocitationMcConnell, Lucas Henry. <i>"Suppression of the fake lepton background in same-sign W-boson scattering with the ATLAS experiment."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Physics, 2017. http://hdl.handle.net/11427/27311en_ZA
dc.identifier.citationMcConnell, L. 2017. Suppression of the fake lepton background in same-sign W-boson scattering with the ATLAS experiment. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - McConnell, Lucas Henry AB - Same-sign W-boson scattering is a rare Standard Model process that is useful for probing the nature of electroweak symmetry breaking and the Higgs mechanism. Analysis is currently underway to measure the cross-section to a significance of 5σ or higher using √s = 13 TeV data from the ATLAS detector's Run 2. The two scattered W-bosons decay leptonically leaving a distinctive experimental signature of two same-sign leptons, two forward jets, and missing transverse energy carried away by two neutrinos. Non-prompt leptons are defined as leptons coming from the decay of hadrons. Such leptons, together with jets misreconstructed as leptons, contribute to the background processes in same-sign W-boson scattering; making up the so-called fake lepton background. In this thesis the fake lepton background is suppressed using two strategies: 1) implementing an optimised veto on events found to contain a b-jet; and 2) optimising the isolation requirements set on signal lepton candidates using the cumulative significance quantity. The approach using the cumulative significance is then extended to optimise additional analysis cuts on the lepton invariant mass mₗₗ, jet invariant mass mⱼⱼ , and the jet separation rapidity Δyⱼⱼ. DA - 2017 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2017 T1 - Suppression of the fake lepton background in same-sign W-boson scattering with the ATLAS experiment TI - Suppression of the fake lepton background in same-sign W-boson scattering with the ATLAS experiment UR - http://hdl.handle.net/11427/27311 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/27311
dc.identifier.vancouvercitationMcConnell LH. Suppression of the fake lepton background in same-sign W-boson scattering with the ATLAS experiment. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Physics, 2017 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/27311en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Physicsen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherPhysicsen_ZA
dc.subject.otherParticle Physicsen_ZA
dc.titleSuppression of the fake lepton background in same-sign W-boson scattering with the ATLAS experimenten_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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