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Targeting Natural Supersymmetry With Top Quarks / T. Christian Herwig.
- Format:
- Book
- Thesis/Dissertation
- Author/Creator:
- Herwig, T. Christian, author.
- Language:
- English
- Subjects (All):
- Quantum physics.
- Particle physics.
- Physics and Astronomy--Penn dissertations.
- Penn dissertations--Physics and Astronomy.
- Local Subjects:
- Quantum physics.
- Particle physics.
- Physics and Astronomy--Penn dissertations.
- Penn dissertations--Physics and Astronomy.
- Genre:
- Academic theses.
- Physical Description:
- 1 online resource (306 pages)
- Contained In:
- Dissertations Abstracts International 81-05B.
- Place of Publication:
- [Philadelphia, Pennsylvania] : University of Pennsylvania ; Ann Arbor : ProQuest Dissertations & Theses, 2019.
- Language Note:
- English
- System Details:
- Mode of access: World Wide Web.
- text file
- Summary:
- This thesis describes a search for natural supersymmetry via the production of light top squarks (stops) with the ATLAS experiment, using 13 TeV proton-proton collision data delivered by the Large Hadron Collider. A range of models is considered where the stop may decay to top quarks, b jets, and a variety of other supersymmetric particles. Stop masses as large as 950 GeV are excluded at 95% confidence level when decaying to a top quark and massless lightest supersymmetric particle (LSP). In scenarios where the LSP is a Higgsino, exclusions vary from 600 to 900 GeV depending on the relative stop branching fractions and Higgsino mass splitting. The impact of precision top-quark measurements on future searches is also discussed, including a measurement of quantum interference in top-quark production and measurement of the top-quark width. A differential mass distribution is measured in events with two charged leptons and two b-tagged jets that is sensitive to the interference property. The measurement is unfolded to particle level and the data are compared to state-of-the-art Monte Carlo predictions, which are found to describe the data well. A new technique is proposed to utilize this dataset to extract a value of the top-quark width, inspired by recent efforts to measure the Higgs boson width using off-shell decays. A value of 1.28 ± 0.27(exp.)±0.15(theory) GeV is extracted from the ATLAS data, in good agreement with the standard model prediction. Finally, a new hardware tracking system is described for use in the upgraded ATLAS Trigger system for the high-luminosity run of the LHC.
- Notes:
- Source: Dissertations Abstracts International, Volume: 81-05, Section: B.
- Advisors: Lipeles, Elliot; Committee members: Justin Khoury; Joseph Kroll; Elliot Lipeles; Evelyn Thomson; Burt Ovrut.
- Department: Physics and Astronomy.
- Ph.D. University of Pennsylvania 2019.
- Local Notes:
- School code: 0175
- ISBN:
- 9781088353578
- Access Restriction:
- Restricted for use by site license.
- This item must not be sold to any third party vendors.
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