The Top Quark as a Window to Beyond the Standard Model Physics

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (857 download)

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Book Synopsis The Top Quark as a Window to Beyond the Standard Model Physics by :

Download or read book The Top Quark as a Window to Beyond the Standard Model Physics written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark was the last of the Standard Model quarks to be discovered, and is of considerable interest. The closeness of the top quark mass to the electroweak scale is suggestive that the top quark could be closely related to the mechanisms for electroweak symmetry breaking. Any new physics in electroweak symmetry breaking models could then preferentially couple to the top quark, making the top quark a promising probe for new physics. In this thesis, we will explore two aspects of the top quark as a harbinger to new physics: the top forward-backward asymmetry as seen at the Tevatron and the search for stops. In this thesis, we will discuss the Asymmetric Left-Right Model (ALRM), a model that is based on the gauge group U'(1)SU(2)SU'(2) with couplings g'_1, g'_2, and g' associated with the fields B', W, W' , respectively, and show how this model can explain the top forward- backward asymmetry. We will then explore the scalar sector of the ALRM, and provide a specific Higgs mechanism that provides the masses for the W' and Z' bosons. The top forward-backward asymmetry is a test of invariance of charge conjugation. Thus, we look at the X-gluon model, a model that was motivated by the top forward-backward asymmetry, and show that one can look at the longitudinal polarization of the top-quark to test parity conservation. Finally, we investigate searches for stop squarks, the supersymmetric partner of the top quark, at the Large Hadron Collider (LHC) using shape-based analyses.

Measurements and Searches with Top Quarks

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ISBN 13 :
Total Pages : 254 pages
Book Rating : 4.:/5 (727 download)

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Book Synopsis Measurements and Searches with Top Quarks by :

Download or read book Measurements and Searches with Top Quarks written by and published by . This book was released on 2008 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1995 the last missing member of the known families of quarks, the top quark, was discovered by the CDF and D0 experiments at the Tevatron, a proton-antiproton collider at Fermilab near Chicago. Until today, the Tevatron is the only place where top quarks can be produced. The determination of top quark production and properties is crucial to understand the Standard Model of particle physics and beyond. The most striking property of the top quark is its mass--of the order of the mass of a gold atom and close to the electroweak scale--making the top quark not only interesting in itself but also as a window to new physics. Due to the high mass, much higher than of any other known fermion, it is expected that the top quark plays an important role in electroweak symmetry breaking, which is the most prominent candidate to explain the mass of particles. In the Standard Model, electroweak symmetry breaking is induced by one Higgs field, producing one additional physical particle, the Higgs boson. Although various searches have been performed, for example at the Large Electron Positron Collider (LEP), no evidence for the Higgs boson could yet be found in any experiment. At the Tevatron, multiple searches for the last missing particle of the Standard Model are ongoing with ever higher statistics and improved analysis techniques. The exclusion or verification of the Higgs boson can only be achieved by combining many techniques and many final states and production mechanisms. As part of this thesis, the search for Higgs bosons produced in association with a top quark pair (t{bar t}H) has been performed. This channel is especially interesting for the understanding of the coupling between Higgs and the top quark. Even though the Standard Model Higgs boson is an attractive candidate, there is no reason to believe that the electroweak symmetry breaking is induced by only one Higgs field. In many models more than one Higgs boson are expected to exist, opening even more channels to search for charged or neutral Higgs bosons. Depending on its mass, the charged Higgs boson is expected to decay either into top quarks or be the decay product of a top quark. For masses below the top quark mass, the top decay into a charged Higgs boson and a b quark can occur at a certain rate, additionally to the decays into W bosons and a b quark. The different decays of W and charged Higgs bosons can lead to deviations of the observed final number of events in certain final states with respect to the Standard Model expectation. A global search for charged Higgs bosons in top quark pair events is presented in this thesis, resulting in the most stringent limits to-date. Besides the decay of top quarks into charged Higgs or W bosons, new physics can also show up in the quark part of the decay. While in the Standard Model the top quark decays with a rate of about 100% into a W boson and a b quark, there are models where the top quark can decay into a W boson and a non-b quark. The ratio of branching fractions in which the top quark decays into a b quark over the branching fractions in which the top quark decays into all quarks is measured as part of this thesis, yielding the most precise measurement today. Furthermore, the Standard Model top quark pair production cross section is essential to be known precisely since the top quark pair production is the main background for t{bar t}H production and many other Higgs and beyond the Standard Model searches. However, not only the search or the test of the Standard Model itself make the precise measurement of the top quark pair production cross section interesting. As the cross section is calculated with high accuracy in perturbative QCD, a comparison of the measurement to the theory expectation yields the possibility to extract the top quark mass from the cross section measurement. Although many dedicated techniques exist to measure the top quark mass, the extraction from the cross section represents an important complementary measurement. The latter is briefly discussed in this thesis and compared to direct top mass measurements. The goal of this thesis is the improved understanding of the top quark sector and its use as a window to new physics. Techniques are extended and developed to measure the top quark pair production cross section simultaneously with the ratio of branching fractions, the t{bar t}H cross section or the rate with which top quarks decay into charged Higgs bosons. Some of the results are then taken to extract more information. The cross section measurement is used to extract the top quark mass, and the ratio of the top quark pair production cross sections in different final states, yielding a limit on non-Standard Model top quark decays.

Discovery of Single Top Quark Production

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Publisher : Springer Science & Business Media
ISBN 13 : 1441977996
Total Pages : 149 pages
Book Rating : 4.4/5 (419 download)

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Book Synopsis Discovery of Single Top Quark Production by : Dag Gillberg

Download or read book Discovery of Single Top Quark Production written by Dag Gillberg and published by Springer Science & Business Media. This book was released on 2011-01-22 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark is by far the heaviest known fundamental particle with a mass nearing that of a gold atom. Because of this strikingly high mass, the top quark has several unique properties and might play an important role in electroweak symmetry breaking—the mechanism that gives all elementary particles mass. Creating top quarks requires access to very high energy collisions, and at present only the Tevatron collider at Fermilab is capable of reaching these energies. Until now, top quarks have only been observed produced in pairs via the strong interaction. At hadron colliders, it should also be possible to produce single top quarks via the electroweak interaction. Studies of single top quark production provide opportunities to measure the top quark spin, how top quarks mix with other quarks, and to look for new physics beyond the standard model. Because of these interesting properties, scientists have been looking for single top quarks for more than 15 years. This thesis presents the first discovery of single top quark production. It documents one of the flagship measurements of the D0 experiment, a collaboration of more than 600 physicists from around the world. It describes first observation of a physical process known as “single top quark production”, which had been sought for more than 10 years before its eventual discovery in 2009. Further, his thesis describes, in detail, the innovative approach Dr. Gillberg took to this analysis. Through the use of Boosted Decision Trees, a machine-learning technique, he observed the tiny single top signal within an otherwise overwhelming background. This Doctoral Thesis has been accepted by Simon Fraser University, Burnaby, BC, Canada.

The Top Quark (20 Years After the Discovery).

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ISBN 13 :
Total Pages : 69 pages
Book Rating : 4.:/5 (96 download)

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Book Synopsis The Top Quark (20 Years After the Discovery). by :

Download or read book The Top Quark (20 Years After the Discovery). written by and published by . This book was released on 2015 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: On the twentieth anniversary of the observation of the top quark, we trace our understanding of this heaviest of all known particles from the prediction of its existence, through the searches and discovery, to the current knowledge of its production mechanisms and properties. We also discuss the central role of the top quark in the Standard Model and the windows that it opens for seeking new physics beyond the Standard Model.

Colliders and Neutrinos

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Publisher : World Scientific
ISBN 13 : 9812819266
Total Pages : 713 pages
Book Rating : 4.8/5 (128 download)

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Book Synopsis Colliders and Neutrinos by : Sally Dawson

Download or read book Colliders and Neutrinos written by Sally Dawson and published by World Scientific. This book was released on 2008 with total page 713 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of theoretical advanced summer institute lectures by world experts in the field of collider physics and neutrinos, the two frontier areas of particle physics today. It is aimed at graduate students and beginning researchers, and as such, provides many pedagogical details not generally available in standard conference proceedings.

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

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Publisher : Springer Science & Business Media
ISBN 13 : 364214070X
Total Pages : 155 pages
Book Rating : 4.6/5 (421 download)

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Book Synopsis Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method by : Alexander Grohsjean

Download or read book Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method written by Alexander Grohsjean and published by Springer Science & Business Media. This book was released on 2010-10-01 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Colliders And Neutrinos: The Window Into Physics Beyond The Standard Model (Tasi 2006)

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Publisher : World Scientific
ISBN 13 : 9814470627
Total Pages : 716 pages
Book Rating : 4.8/5 (144 download)

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Book Synopsis Colliders And Neutrinos: The Window Into Physics Beyond The Standard Model (Tasi 2006) by : Sally Dawson

Download or read book Colliders And Neutrinos: The Window Into Physics Beyond The Standard Model (Tasi 2006) written by Sally Dawson and published by World Scientific. This book was released on 2008-08-20 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of theoretical advanced summer institute lectures by world experts in the field of collider physics and neutrinos, the two frontier areas of particle physics today. It is aimed at graduate students and beginning researchers, and as such, provides many pedagogical details not generally available in standard conference proceedings.

Perspectives on Lhc Physics

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Publisher : World Scientific
ISBN 13 : 9812779760
Total Pages : 352 pages
Book Rating : 4.8/5 (127 download)

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Book Synopsis Perspectives on Lhc Physics by : G. L. Kane

Download or read book Perspectives on Lhc Physics written by G. L. Kane and published by World Scientific. This book was released on 2008 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Large Hadron Collider (LHC), located at CERN, Geneva, Switzerland, is the world's largest and highest energy and highest intensity particle accelerator. Here is a timely book with several perspectives on the hoped-for discoveries from the LHC.This book provides an overview on the techniques that will be crucial for finding new physics at the LHC, as well as perspectives on the importance and implications of the discoveries. Among the accomplished contributors to this book are leaders and visionaries in the field of particle physics beyond the Standard Model, including two Nobel Laureates (Steven Weinberg and Frank Wilczek), and presumably some future Nobel Laureates, plus top younger theorists and experimenters. With its blend of popular and technical contents, the book will have wide appeal, not only to physical scientists but also to those in related fields.

Physics at the Terascale

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Publisher : John Wiley & Sons
ISBN 13 : 3527634975
Total Pages : 437 pages
Book Rating : 4.5/5 (276 download)

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Book Synopsis Physics at the Terascale by : Ian Brock

Download or read book Physics at the Terascale written by Ian Brock and published by John Wiley & Sons. This book was released on 2011-05-04 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by authors working at the forefront of research, this accessible treatment presents the current status of the field of collider-based particle physics at the highest energies available, as well as recent results and experimental techniques. It is clearly divided into three sections; The first covers the physics -- discussing the various aspects of the Standard Model as well as its extensions, explaining important experimental results and highlighting the expectations from the Large Hadron Collider (LHC). The second is dedicated to the involved technologies and detector concepts, and the third covers the important - but often neglected - topics of the organisation and financing of high-energy physics research. A useful resource for students and researchers from high-energy physics.

Properties of the Top Quark

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ISBN 13 :
Total Pages : 141 pages
Book Rating : 4.:/5 (727 download)

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Book Synopsis Properties of the Top Quark by :

Download or read book Properties of the Top Quark written by and published by . This book was released on 2009 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of particle physics is the understanding of elementary particles and their interactions. The current theory of elementary particle physics, the Standard Model, contains twelve different types of fermions which (neglecting gravity) interact through the gauge bosons of three forces. In addition a scalar particle, the Higgs boson, is needed for theoretical consistency. These few building blocks explain all experimental results found in the context of particle physics, so far. Nevertheless, it is believed that the Standard Model is only an approximation to a more complete theory. First of all the fourth known force, gravity, has withstood all attempts to be included until now. Furthermore, the Standard Model describes several features of the elementary particles like the existence of three families of fermions or the quantisation of charges, but does not explain these properties from underlying principles. Finally, the lightness of the Higgs boson needed to explain the symmetry breaking is difficult to maintain in the presence of expected corrections from gravity at high scales. This is the so called hierarchy problem. In addition astrophysical results indicate that the universe consists only to a very small fraction of matter described by the Standard Model. Large fractions of dark energy and dark matter are needed to describe the observations. Both do not have any correspondence in the Standard Model. Also the very small asymmetry between matter and anti-matter that results in the observed universe built of matter (and not of anti-matter) cannot be explained until now. It is thus an important task of experimental particle physics to test the predictions of the Standard Model to the best possible accuracy and to search for deviations pointing to necessary extensions or modifications of our current theoretical understanding. The top quark was predicted to exist by the Standard Model as the partner of the bottom quark. It was first observed in 1995 by the Tevatron experiments CDF and D0 and was the last of the quarks to be discovered. As the partner of the bottom quark the top quark is expected to have quantum numbers identical to that of the other known up-type quarks. Only the mass is a free parameter. We now know that it is more than 30 times heavier than the next heaviest quark, the bottom quark. Thus, within the Standard Model all production and decay properties are fully defined. Having the complete set of quarks further allows to verify constraints that the Standard Model puts on the sum of all quarks or particles. This alone is reason enough to experimentally study the top quark properties. The high value of the top quark mass and its closeness to the electroweak scale has inspired people to speculate that the top quark could have a special role in the electroweak symmetry breaking. Confirming the expected properties of the top quark experimentally establishes the top quark as we expect it to be. Any deviation from the expectations gives hints to new physics that may help to solve the outstanding questions. In this review the recent results on top quark properties obtained by the Tevatron experiments CDF and D0 are summarized. At the advent of the LHC special emphasis is given to the basic measurement methods and the dominating systematic uncertainties. After a short introduction to the Standard Model and the experimental environment in the remainder of this chapter, Chapter 2 describes the current status of top quark mass measurements. Then measurments of interaction properties are described in Chapter 3. Finally, Chapter 4 deals with analyses that consider hypothetical particles beyond the Standard Model in the observed events.

Particle And Astroparticle Physics, Gravitation And Cosmology: Predictions, Observations And New Projects - Proceedings Of The Xxx-th International Workshop On High Energy Physics

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Publisher : World Scientific
ISBN 13 : 9814689319
Total Pages : 380 pages
Book Rating : 4.8/5 (146 download)

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Book Synopsis Particle And Astroparticle Physics, Gravitation And Cosmology: Predictions, Observations And New Projects - Proceedings Of The Xxx-th International Workshop On High Energy Physics by : Roman Anatolievich Ryutin

Download or read book Particle And Astroparticle Physics, Gravitation And Cosmology: Predictions, Observations And New Projects - Proceedings Of The Xxx-th International Workshop On High Energy Physics written by Roman Anatolievich Ryutin and published by World Scientific. This book was released on 2015-06-16 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique volume captures the content of the XXXth International Workshop on High Energy Physics. The scope of this volume is much wider than just high-energy physics; it actually concerns and includes materials from all the most fundamental areas of modern physics research: high-energy physics proper, gravitation and cosmology. Presentations embrace both theory and experiment.

Beyond The Standard Model Iv

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Publisher : World Scientific
ISBN 13 : 9814549215
Total Pages : 650 pages
Book Rating : 4.8/5 (145 download)

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Book Synopsis Beyond The Standard Model Iv by : Tao Han

Download or read book Beyond The Standard Model Iv written by Tao Han and published by World Scientific. This book was released on 1995-08-31 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings contain over 100 talks on all aspects of Physics Beyond the Standard Model of the strong and electroweak interactions — ranging from Supersymmetry, Grand Unification, Technicolor, Exotic Particles, and CP Violation to Baryogenesis, Dark Matter, Strings and Black Holes — by leading authorities and the most active researchers in High Energy Physics. The goal of the conference is to provide a completely current summary of the most exciting and aesthetically appealing theoretical ideas, especially with regard to their predictions for yet undiscovered new particles, interactions and consequent phenomena. Particular emphasis is placed on current experimental limits and constraints on new physics, and on expectations and predictions regarding our ability to probe and discriminate between the many possibilities through experiments at present and future colliders in the decade(s) to come.

Top Quark Physics at Hadron Colliders

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Publisher : Springer Science & Business Media
ISBN 13 : 3540710604
Total Pages : 166 pages
Book Rating : 4.5/5 (47 download)

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Book Synopsis Top Quark Physics at Hadron Colliders by : Arnulf Quadt

Download or read book Top Quark Physics at Hadron Colliders written by Arnulf Quadt and published by Springer Science & Business Media. This book was released on 2007-08-16 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like?

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Publisher : Frontiers Media SA
ISBN 13 : 2889639908
Total Pages : 180 pages
Book Rating : 4.8/5 (896 download)

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Book Synopsis Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like? by : Roman Pasechnik

Download or read book Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like? written by Roman Pasechnik and published by Frontiers Media SA. This book was released on 2020-09-03 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Particle Physics at the Year of Astronomy

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Publisher : World Scientific
ISBN 13 : 9814329681
Total Pages : 472 pages
Book Rating : 4.8/5 (143 download)

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Book Synopsis Particle Physics at the Year of Astronomy by : A. I. Studenikin

Download or read book Particle Physics at the Year of Astronomy written by A. I. Studenikin and published by World Scientific. This book was released on 2011 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings are devoted to a wide variety of both theoretical and experimental areas in particle physics. The topics include physics at accelerators and studies of Standard Model and Beyond, neutrino and astroparticle physics, cosmology, CP Violation and rare decays, hadron physics, and new developments in quantum field theory. The papers of the volume reveal the present status and new development in the above mentioned items. In particular, the first results on measurement of LHC pp collision events are also reported.

Top Quark Pair Production

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Publisher : Springer Science & Business Media
ISBN 13 : 3319014870
Total Pages : 231 pages
Book Rating : 4.3/5 (19 download)

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Book Synopsis Top Quark Pair Production by : Anna Christine Henrichs

Download or read book Top Quark Pair Production written by Anna Christine Henrichs and published by Springer Science & Business Media. This book was released on 2013-10-04 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Measurement of the Top Quark Coupling to the Z Boson, and Applications to Searches for Physics Beyond the Standard Model

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (122 download)

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Book Synopsis Measurement of the Top Quark Coupling to the Z Boson, and Applications to Searches for Physics Beyond the Standard Model by : Baptiste Ravina

Download or read book Measurement of the Top Quark Coupling to the Z Boson, and Applications to Searches for Physics Beyond the Standard Model written by Baptiste Ravina and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: