Top Quark Spin Correlations With The Cms Detector
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Top Quark Spin Correlations With The Cms Detector
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Author : Jason R. Thieman
language : en
Publisher: Springer Nature
Release Date : 2024-12-04
Top Quark Spin Correlations With The Cms Detector written by Jason R. Thieman and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-12-04 with Science categories.
The differential top quark precision measurements of polarizations and spin correlations presented in this dissertation may potentially lead to breakthroughs in several key areas: observing quantum entanglement and Bell's Inequality violations in a hadronic system, discovering toponium, illuminating supersymmetry, interpreting field theories beyond the Standard Model, and advancing the understanding of electroweak vacuum stability. Additionally, this thesis provides a significantly improved understanding of CMS detector lepton trigger efficiencies, which has greatly enhanced the search for Lorentz invariance violation in top quark events, boosting the sensitivity by greater than a factor of 100. Finally, the thesis includes TCAD simulations that explore the feasibility of using the initial transient induced current, as described by the Ramo-Shockley Theorem, to achieve the picosecond timing precision in silicon pixel detectors needed for four-dimensional tracking.
Spin Correlations In Tt Events From Pp Collisions
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Author : Boris Lemmer
language : en
Publisher: Springer
Release Date : 2015-06-24
Spin Correlations In Tt Events From Pp Collisions written by Boris Lemmer and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-06-24 with Science categories.
This thesis introduces readers to the Standard Model, the top quark and its properties, before explaining the concept of spin correlation measurement. The first measurement of top quark spin correlations at the LHC in the lepton+jets decay channel is presented. As the heaviest elementary particle, the top quark plays an essential role in the Standard Model of elementary particle physics. In the case of top quarks being produced in pairs at hadron colliders, the Standard Model predicts their spins to be correlated. The degree of correlation depends on both the production mechanism and properties of the top quark. Any deviation from the Standard Model prediction can be an indicator for new physics phenomena. The thesis employs an advanced top quark reconstruction algorithm including dedicated identification of the up- and down-type quarks from the W boson decay.
Cms Pixel Detector Upgrade And Top Quark Pole Mass Determination
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Author : Simon Spannagel
language : en
Publisher: Springer
Release Date : 2017-08-01
Cms Pixel Detector Upgrade And Top Quark Pole Mass Determination written by Simon Spannagel and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-08-01 with Science categories.
This thesis addresses two different topics, both vital for implementing modern high-energy physics experiments: detector development and data analysis. Providing a concise introduction to both the standard model of particle physics and the basic principles of semiconductor tracking detectors, it presents the first measurement of the top quark pole mass from the differential cross-section of tt+J events in the dileptonic tt decay channel. The first part focuses on the development and characterization of silicon pixel detectors. To account for the expected increase in luminosity of the Large Hadron Collider (LHC), the pixel detector of the compact muon solenoid (CMS) experiment is replaced by an upgraded detector with new front-end electronics. It presents comprehensive test beam studies conducted to verify the design and quantify the performance of the new front-end in terms of tracking efficiency and spatial resolution. Furthermore, it proposes a new cluster interpolation method, which utilizes the third central moment of the cluster charge distribution to improve the position resolution. The second part of the thesis introduces an alternative measurement of the top quark mass from the normalized differential production cross-sections of dileptonic top quark pair events with an additional jet. The energy measurement is 8TeV. Using theoretical predictions at next-to-leading order in perturbative Quantum Chromodynamics (QCD), the top quark pole mass is determined using a template fit method.
Fundamental Interactions
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Author : A. Astbury
language : en
Publisher: World Scientific
Release Date : 2006
Fundamental Interactions written by A. Astbury and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with Science categories.
This proceedings volume contains the latest developments in particle physics in collider experiments. The contributions cover new results such as the production of quark-gluon plasma in the heavy-ion collider, the new techniques for precision measurement at low energies, and the status of neutrino physics at various laboratories including the new facilities that are at the planning stage.
Fundamental Interactions Proceedings Of The 21st Lake Louise Winter Institute
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Author : Alan Astbury
language : en
Publisher: World Scientific
Release Date : 2006-12-29
Fundamental Interactions Proceedings Of The 21st Lake Louise Winter Institute written by Alan Astbury and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-12-29 with Science categories.
This proceedings volume contains the latest developments in particle physics in collider experiments. The contributions cover new results such as the production of quark-gluon plasma in the heavy-ion collider, the new techniques for precision measurement at low energies, and the status of neutrino physics at various laboratories including the new facilities that are at the planning stage.
Fundamental Interactions Proceedings Of The 23rd Lake Louise Winter Institute 2008
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Author : Alan Astbury
language : en
Publisher: World Scientific
Release Date : 2009-09-03
Fundamental Interactions Proceedings Of The 23rd Lake Louise Winter Institute 2008 written by Alan Astbury and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009-09-03 with Science categories.
This book contains pedagogical lectures on both theoretical and experimental particle physics, cosmology, and atomic trap physics. Numerous additional contributions provide up-to-date information on new experimental results from accelerators, underground laboratories, and nuclear astrophysics. This combination of pedagogical talks and topical short discussions presents a comprehensive amount of information and latest developments to researchers.
Fundamental Interactions
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Author : Alan Astbury
language : en
Publisher: World Scientific
Release Date : 2009
Fundamental Interactions written by Alan Astbury and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with Science categories.
This book contains pedagogical lectures on both theoretical and experimental particle physics, cosmology, and atomic trap physics. Numerous additional contributions provide up-to-date information on new experimental results from accelerators, underground laboratories, and nuclear astrophysics. This combination of pedagogical talks and topical short discussions presents a comprehensive amount of information and latest developments to researchers.
Search For Scalar Top Quarks And Higgsino Like Neutralinos
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Author : Takuya Nobe
language : en
Publisher: Springer
Release Date : 2015-11-30
Search For Scalar Top Quarks And Higgsino Like Neutralinos written by Takuya Nobe and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-11-30 with Science categories.
This book reports a search for theoretically natural supersymmetry (SUSY) at the Large Hadron Collider (LHC). The data collected with the ATLAS detector in 2012 corresponding to 20 /fb of an integrated luminosity have been analyzed for stop pair production in proton–proton collisions at a center-of-mass energy of 8 TeV at the Large Hadron Collider (LHC) in the scenario of the higgsino-like neutralino. The author focuses on stop decaying into a bottom quark and chargino. In the scenario of the higgsino-like neutralino, the mass difference between charginos and neutralinos (Δm) is expected to be small, and observable final-state particles are likely to have low-momentum (soft). The author develops a dedicated analysis with a soft lepton as a probe of particles from chargino decay, which suppresses the large amount of backgrounds. As a result of the analysis, no significant SUSY signal is observed. The 95% confidence-level exclusion limits are set to masses of stop and neutralino assuming Δm = 20 GeV. The region with ΔM (the mass difference between stop and neutralino) 70 GeV is excluded for the first time at stop mass of less than 210 GeV. The author also excludes the signals with ΔM 120 GeV up to 600 GeV of stop mass with neutralino mass of less than 280 GeV. The author clearly shows very few remaining parameter spaces for light stop (e.g., topology of stop decay is extremely similar to the SM top quark) by combining his results and previous ATLAS analyses. His results provide a strong constraint to searches for new physics in the future.
Search For The Higgs Boson Produced In Association With Top Quarks With The Cms Detector At The Lhc
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Author : Cristina Martin Perez
language : en
Publisher: Springer Nature
Release Date : 2022-02-09
Search For The Higgs Boson Produced In Association With Top Quarks With The Cms Detector At The Lhc written by Cristina Martin Perez and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-02-09 with Science categories.
In this work, the interaction between the Higgs boson and the top quark is studied with the proton-proton collisions at 13 TeV provided by the LHC at the CMS detector at CERN (Geneva). At the LHC, these particles are produced simultaneously via the associate production of the Higgs boson with one top quark (tH process) or two top quarks (ttH process). Compared to many other possible outcomes of the proton-proton interactions, these processes are very rare, as the top quark and the Higgs boson are the heaviest elementary particles known. Hence, identifying them constitutes a significant experimental challenge. A high particle selection efficiency in the CMS detector is therefore crucial. At the core of this selection stands the Level-1 (L1) trigger system, a system that filters collision events to retain only those with potential interest for physics analysis. The selection of hadronically decaying τ leptons, expected from the Higgs boson decays, is especially demanding due to the large background arising from the QCD interactions. The first part of this thesis presents the optimization of the L1 τ algorithm in Run 2 (2016-2018) and Run 3 (2022-2024) of the LHC. It includes the development of a novel trigger concept for the High-Luminosity LHC, foreseen to start in 2027 and to deliver 5 times the current instantaneous luminosity. To this end, sophisticated algorithms based on machine learning approaches are used, facilitated by the increasingly modern technology and powerful computation of the trigger system. The second part of the work presents the search of the tH and ttH processes with the subsequent decays of the Higgs boson to pairs of τ lepton, W bosons or Z bosons, making use of the data recorded during Run 2. The presence of multiple particles in the final state, along with the low cross section of the processes, makes the search an ideal use case for multivariant discriminants that enhance the selectivity of the signals and reject the overwhelming background contributions. The discriminants presented are built using state-of-the-art machine learning techniques, able to capture the correlations amongst the processes involved, as well as the so-called Matrix Element Method (MEM), which combines the theoretical description of the processes with the detector resolution effects. The level of sophistication of the methods used, along with the unprecedented amount of collision data analyzed, result in the most stringent measurements of the tH and ttH cross sections up to date.
Top Quark Pair Production Cross Sections And Calibration Of The Top Quark Monte Carlo Mass
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Author : Jan Kieseler
language : en
Publisher: Springer
Release Date : 2016-06-15
Top Quark Pair Production Cross Sections And Calibration Of The Top Quark Monte Carlo Mass written by Jan Kieseler and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-06-15 with Science categories.
This thesis presents the first experimental calibration of the top-quark Monte-Carlo mass. It also provides the top-quark mass-independent and most precise top-quark pair production cross-section measurement to date. The most precise measurements of the top-quark mass obtain the top-quark mass parameter (Monte-Carlo mass) used in simulations, which are partially based on heuristic models. Its interpretation in terms of mass parameters used in theoretical calculations, e.g. a running or a pole mass, has been a long-standing open problem with far-reaching implications beyond particle physics, even affecting conclusions on the stability of the vacuum state of our universe. In this thesis, this problem is solved experimentally in three steps using data obtained with the compact muon solenoid (CMS) detector. The most precise top-quark pair production cross-section measurements to date are performed. The Monte-Carlo mass is determined and a new method for extracting the top-quark mass from theoretical calculations is presented. Lastly, the top-quark production cross-sections are obtained – for the first time – without residual dependence on the top-quark mass, are interpreted using theoretical calculations to determine the top-quark running- and pole mass with unprecedented precision, and are fully consistently compared with the simultaneously obtained top-quark Monte-Carlo mass.