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From Bottom to Top: Identification to Precision Measurement of 3rd Generation Quarks with the ATLAS Detector

Sapp, Kevin (2016) From Bottom to Top: Identification to Precision Measurement of 3rd Generation Quarks with the ATLAS Detector. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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The 3rd-generation quarks, bottom (b) and top (t), are recent additions to the Standard Model of particle physics, and precise characterization of their properties have important implications to searching for new physics phenomena. This thesis presents two analyses which use 4.6 fb−1 of pp collision data at √s = 7 TeV collected by the ATLAS detector at the Large Hadron Collider (LHC) to measure their properties. The first is an analysis which measures our ability to identify jets originating from b quarks with machine-learning algorithms applied to simulated and real data, so the result in simulation can be corrected to match that in data. This measurement has implications for our ability to identify processes with b quarks in their final state; t quarks decay to a b quark and a weak vector boson W more than 99% of the time. The second analysis presented measures properties of the t → Wb decay channel associated with phenomena not predicted by the Standard Model, through a set of effective couplings which preserve Lorentz covariance. The kinematic information of the final-state particles is used to construct an event-specific coordinate system, and probability density is estimated as a function of solid angle in these coordinates. A parameterization of the effective couplings is extracted via a novel unfolding method, finding their values consistent with the Standard Model expectation, contributing the first measurement of the correlation between the parameters, and improving on previous limits.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Sapp, Kevink.carr.sapp@gmail.comKCS340000-0001-9304-3090
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairMueller, Jamesmueller@pitt.eduMUELLER
Date: 15 June 2016
Date Type: Publication
Defense Date: 10 December 2015
Approval Date: 15 June 2016
Submission Date: 11 January 2016
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 218
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Physics
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: LHC, ATLAS Experiment, Top Quark, b-tagging, Electroweak Physics, Heavy-flavor Physics
Date Deposited: 15 Jun 2016 15:57
Last Modified: 15 Nov 2016 14:31


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