Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method

Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method

Author: Alexander Grohsjean

Publisher: Springer Science & Business Media

Published: 2010-10-01

Total Pages: 155

ISBN-13: 364214070X

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The main pacemakers of scienti?c research are curiosity, ingenuity, and a pinch of persistence. Equipped with these characteristics a young researcher will be s- cessful in pushing scienti?c discoveries. And there is still a lot to discover and to understand. In the course of understanding the origin and structure of matter it is now known that all matter is made up of six types of quarks. Each of these carry a different mass. But neither are the particular mass values understood nor is it known why elementary particles carry mass at all. One could perhaps accept some small generic mass value for every quark, but nature has decided differently. Two quarks are extremely light, three more have a somewhat typical mass value, but one quark is extremely massive. It is the top quark, the heaviest quark and even the heaviest elementary particle that we know, carrying a mass as large as the mass of three iron nuclei. Even though there exists no explanation of why different particle types carry certain masses, the internal consistency of the currently best theory—the standard model of particle physics—yields a relation between the masses of the top quark, the so-called W boson, and the yet unobserved Higgs particle. Therefore, when one assumes validity of the model, it is even possible to take precise measurements of the top quark mass to predict the mass of the Higgs (and potentially other yet unobserved) particles.


Top Quark Physics at Hadron Colliders

Top Quark Physics at Hadron Colliders

Author: Arnulf Quadt

Publisher: Springer Science & Business Media

Published: 2007-08-16

Total Pages: 166

ISBN-13: 3540710604

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This will be a required acquisition text for academic libraries. More than ten years after its discovery, still relatively little is known about the top quark, the heaviest known elementary particle. This extensive survey summarizes and reviews top-quark physics based on the precision measurements at the Fermilab Tevatron Collider, as well as examining in detail the sensitivity of these experiments to new physics. Finally, the author provides an overview of top quark physics at the Large Hadron Collider.


Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass

Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass

Author: Jan Kieseler

Publisher: Springer

Published: 2016-06-15

Total Pages: 172

ISBN-13: 3319400053

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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.


Top Quark Pair Production

Top Quark Pair Production

Author: Anna Christine Henrichs

Publisher: Springer Science & Business Media

Published: 2013-10-04

Total Pages: 231

ISBN-13: 3319014870

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Before any kind of new physics discovery could be made at the LHC, a precise understanding and measurement of the Standard Model of particle physics' processes was necessary. The book provides an introduction to top quark production in the context of the Standard Model and presents two such precise measurements of the production of top quark pairs in proton-proton collisions at a center-of-mass energy of 7 TeV that were observed with the ATLAS Experiment at the LHC. The presented measurements focus on events with one charged lepton, missing transverse energy and jets. Using novel and advanced analysis techniques as well as a good understanding of the detector, they constitute the most precise measurements of the quantity at that time.


First Measurement of the Running of the Top Quark Mass

First Measurement of the Running of the Top Quark Mass

Author: Matteo M. Defranchis

Publisher: Springer Nature

Published: 2022-01-03

Total Pages: 170

ISBN-13: 3030903761

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In this thesis, the first measurement of the running of the top quark mass is presented. This is a fundamental quantum effect that had never been studied before. Any deviation from the expected behaviour can be interpreted as a hint of the presence of physics beyond the Standard Model. All relevant aspects of the analysis are extensively described and documented. This thesis also describes a simultaneous measurement of the inclusive top quark-antiquark production cross section and the top quark mass in the simulation. The measured cross section is also used to precisely determine the values of the top quark mass and the strong coupling constant by comparing to state-of-the-art theoretical predictions. All the theoretical and experimental aspects relevant to the results presented in this thesis are discussed in the initial chapters in a concise but complete way, which makes the material accessible to a wider audience.


XIX International Symposium on Lepton and Photon Interactions at High Energies

XIX International Symposium on Lepton and Photon Interactions at High Energies

Author: John Jaros

Publisher: World Scientific

Published: 2000

Total Pages: 952

ISBN-13: 9789810241896

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Stanford University hosted the XIX International Symposium on Lepton and Photon Interactions at High Energies on August 9 - 14, 1999, at the Law School on the Stanford University Campus, the site of the previous Symposia. This volume constitutes the proceedings of the Symposium.


Fundamental Interactions - Proceedings Of The Nineteenth Lake Louise Winter Institute

Fundamental Interactions - Proceedings Of The Nineteenth Lake Louise Winter Institute

Author: Alan Astbury

Publisher: World Scientific

Published: 2005-04-21

Total Pages: 360

ISBN-13: 9814480681

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This volume contains pedagogical lectures on particle physics, nuclear astrophysics, relativistic heavy ion interactions and gravitational waves. In addition, numerous contributions provide up-to-date information on new experimental results at colliders, underground laboratories and nuclear astrophysics. This combination of pedagogical talks and topical short talks provide a comprehensive amount of information to the researchers.


Particles, Strings And Cosmology - Proceedings Of The John Hopkins Workshop On Current Problems In Particle Theory 19 And The Pascos Interdisciplinary Symposium 5

Particles, Strings And Cosmology - Proceedings Of The John Hopkins Workshop On Current Problems In Particle Theory 19 And The Pascos Interdisciplinary Symposium 5

Author: Gabor Domokos

Publisher: World Scientific

Published: 1996-07-13

Total Pages: 498

ISBN-13: 9814548286

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This was a joint meeting of the Johns Hopkins Workshop and PASCOS. It was interdisciplinary in its nature. The proceedings gives an overview of the current situation in the interrelated fields of elementary particle physics, astrophysics and cosmology as well as provides a forum for the presentation new results.


Particles And The Universe: Proceedings Of The 12th Lake Winter Institute

Particles And The Universe: Proceedings Of The 12th Lake Winter Institute

Author: Alan Astbury

Publisher: World Scientific

Published: 1998-07-31

Total Pages: 586

ISBN-13: 9814544868

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This volume addresses the important questions at the interface of particle physics, cosmology and nuclear astrophysics. It includes the latest results from LEP 2, primordial nucleosynthesis and dark matter, experiments to measure the cosmic background radiation and experiments in the laboratory with radioactive beams to ascertain the importance of astrophysics in the universe. Also presented are the new results at highest momentum transfer in positron-proton collisions from HERA.