Search for Flavor-Changing Neutral Current Top Quark Decays t → Hq, with H → bb̅ , in pp Collisions at √s = 8 TeV with the ATLAS Detector

Search for Flavor-Changing Neutral Current Top Quark Decays t → Hq, with H → bb̅ , in pp Collisions at √s = 8 TeV with the ATLAS Detector

Author: Shota Tsiskaridze

Publisher: Springer

Published: 2017-08-02

Total Pages: 248

ISBN-13: 3319634143

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This PhD thesis focuses on the search for flavor-changing neutral currents in the decay of a top quark to an up-type quark (q = u, c) and the Standard Model Higgs boson, where the Higgs boson decays to bb. Further, the thesis presents the combination of this search for top quark pair events with other ATLAS searches – in the course of which the most restrictive bounds to date on tqH interactions were obtained. Following on from the discovery of the Higgs boson, it is particularly important to measure the Yukawa couplings of the Standard Model fermions; these parameters may provide crucial insights to help solve the flavor puzzle and may help reveal the presence of new physics before it is directly observed in experiments.


Search for Flavor-changing Neutral Current Top Quark Decays T—›Hq, with H—›bb, in Pp Collisions at √s

Search for Flavor-changing Neutral Current Top Quark Decays T—›Hq, with H—›bb, in Pp Collisions at √s

Author: Shota Tsiskaridze

Publisher:

Published: 2016

Total Pages: 232

ISBN-13: 9788449064845

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Esta tesis presenta la búsqueda de decaimientos del quark top, via corrientes neutras que cambian el sabor, a quarks tipo u (q = u; c) y a el bosón de Higgs del modelo estándar. El análisis busca eventos donde un quark top decae a Wb y el W decae en leptones, mientras que el otro quark top decae a Hq. El estudio se basa en colisiones protón-protón a una energía en el centro de masa de √ s = 8 TeV obtenidas en 2012 con el detector ATLAS del Large Hadron Collider del CERN, usando una muestra de 20.3 fb-1. Los datos corresponden a eventos con un electrón o muon aislado y al menos cuatro jets en el estado final. La búsqueda explota la alta multiplicidad de quarks b que caracterizan la señal, empleando un discriminante basado en la verosimilitud que utiliza las diferencias cinemáticas entre la señal y el fondo (el cual está dominado por eventos tt—›WbWb). No se observan eventos en exceso del fondo esperado. Los límites de un 95% de confianza para el proceso observado (esperado) son de 0.56% (0.42%) para t —›Hc y de 0.61% (0.64%) para t—›Hu. Los límites de esta búsqueda han sido combinados con las búsquedas en los canales con modos de decaimiento H—› y H—›WW*; tt , logrando mejorar significativamente la sensibilidad. Los límites de un 95% de confianza para la combinación observada (esperada) es de 0.46% (0.25%) para t—› Hc y 0.45% (0.29%) para t ! Hu respectivamente. Los límites correspondientes en el acoplamiento.


Physics at the Large Hadron Collider

Physics at the Large Hadron Collider

Author: Amitava Datta

Publisher: Springer Science & Business Media

Published: 2010-05-30

Total Pages: 260

ISBN-13: 8184892950

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In an epoch when particle physics is awaiting a major step forward, the Large Hydron Collider (LHC) at CERN, Geneva will soon be operational. It will collide a beam of high energy protons with another similar beam circulation in the same 27 km tunnel but in the opposite direction, resulting in the production of many elementary particles some never created in the laboratory before. It is widely expected that the LHC will discover the Higgs boson, the particle which supposedly lends masses to all other fundamental particles. In addition, the question as to whether there is some new law of physics at such high energy is likely to be answered through this experiment. The present volume contains a collection of articles written by international experts, both theoreticians and experimentalists, from India and abroad, which aims to acquaint a non-specialist with some basic issues related to the LHC. At the same time, it is expected to be a useful, rudimentary companion of introductory exposition and technical expertise alike, and it is hoped to become unique in its kind. The fact that there is substantial Indian involvement in the entire LHC endeavour, at all levels including fabrication, physics analysis procedures as well as theoretical studies, is also amply brought out in the collection.


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.


Data Analysis in High Energy Physics

Data Analysis in High Energy Physics

Author: Olaf Behnke

Publisher: John Wiley & Sons

Published: 2013-08-30

Total Pages: 452

ISBN-13: 3527653430

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This practical guide covers the essential tasks in statistical data analysis encountered in high energy physics and provides comprehensive advice for typical questions and problems. The basic methods for inferring results from data are presented as well as tools for advanced tasks such as improving the signal-to-background ratio, correcting detector effects, determining systematics and many others. Concrete applications are discussed in analysis walkthroughs. Each chapter is supplemented by numerous examples and exercises and by a list of literature and relevant links. The book targets a broad readership at all career levels - from students to senior researchers. An accompanying website provides more algorithms as well as up-to-date information and links. * Free solutions manual available for lecturers at www.wiley-vch.de/supplements/


Noncommutative Geometry, Quantum Fields and Motives

Noncommutative Geometry, Quantum Fields and Motives

Author: Alain Connes

Publisher: American Mathematical Soc.

Published: 2019-03-13

Total Pages: 810

ISBN-13: 1470450453

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The unifying theme of this book is the interplay among noncommutative geometry, physics, and number theory. The two main objects of investigation are spaces where both the noncommutative and the motivic aspects come to play a role: space-time, where the guiding principle is the problem of developing a quantum theory of gravity, and the space of primes, where one can regard the Riemann Hypothesis as a long-standing problem motivating the development of new geometric tools. The book stresses the relevance of noncommutative geometry in dealing with these two spaces. The first part of the book deals with quantum field theory and the geometric structure of renormalization as a Riemann-Hilbert correspondence. It also presents a model of elementary particle physics based on noncommutative geometry. The main result is a complete derivation of the full Standard Model Lagrangian from a very simple mathematical input. Other topics covered in the first part of the book are a noncommutative geometry model of dimensional regularization and its role in anomaly computations, and a brief introduction to motives and their conjectural relation to quantum field theory. The second part of the book gives an interpretation of the Weil explicit formula as a trace formula and a spectral realization of the zeros of the Riemann zeta function. This is based on the noncommutative geometry of the adèle class space, which is also described as the space of commensurability classes of Q-lattices, and is dual to a noncommutative motive (endomotive) whose cyclic homology provides a general setting for spectral realizations of zeros of L-functions. The quantum statistical mechanics of the space of Q-lattices, in one and two dimensions, exhibits spontaneous symmetry breaking. In the low-temperature regime, the equilibrium states of the corresponding systems are related to points of classical moduli spaces and the symmetries to the class field theory of the field of rational numbers and of imaginary quadratic fields, as well as to the automorphisms of the field of modular functions. The book ends with a set of analogies between the noncommutative geometries underlying the mathematical formulation of the Standard Model minimally coupled to gravity and the moduli spaces of Q-lattices used in the study of the zeta function.


The Higgs Hunter's Guide

The Higgs Hunter's Guide

Author: John F. Gunion

Publisher: CRC Press

Published: 2018-03-05

Total Pages: 333

ISBN-13: 0429976070

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The Higgs Hunter's Guide is a definitive and comprehensive guide to the physics of Higgs bosons. In particular, it discusses the extended Higgs sectors required by those recent theoretical approaches that go beyond the Standard Model, including supersymmetry and superstring-inspired models.


Particle Physics

Particle Physics

Author: Necia Grant Cooper

Publisher: CUP Archive

Published: 1988-04-29

Total Pages: 220

ISBN-13: 9780521347808

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This book explains the emergence of a profoundly new understanding of the fundamental forces of Nature.