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.

Download or read book Seeing a Single Top Quark written by Harish Potti and published by . This book was released on 2020 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark is the heaviest known elementary particle. With a coupling to the Higgs boson close to unity, the top quark plays a special role in electroweak symmetry breaking as well as in physics beyond the Standard Model. An accurate measurement of its properties can provide key information for understanding the physics at the TeV scale. In this dissertation, two measurements of the top quark properties are presented. The first part of this dissertation presents the first-ever ATLAS search for the associated production of a single top quark and a photon. This analysis is performed with 139 fb−1 of pp collision data collected by the ATLAS detector at the LHC at [square root symbol] s = 13 TeV. Only final states with exactly one lepton and at least one photon are considered in this analysis. In the second part, results from the combination of ATLAS searches for flavor changing neutral currents (FCNC) in t->Hq decays are presented. Four FCNC analyses, probing different Higgs decay modes, performed with 36.1 fb−1 of proton-proton collision data collected by the ATLAS detector in 2015-2016 are considered in the combination. They search for top-quark pair events in which one top quark decays into Wb and the other top quark decay into Hq

Download or read book Higher Order QCD Corrections to Single Top Quark Production written by Mohammad Assadsolimani and published by disserta Verlag. This book was released on 2014-08 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is known that the LHC has a considerable discovery potential because of its large centre-of-mass energy (vs =14 TeV) and the high design luminosity. In addition, the two experiments ATLAS and CMS perform precision measurements for numerous models in physics. The increasing experimental precision demands an even higher level of accuracy on the theoretical side. For a more precise prediction of outcomes, one has to consider the corrections obtained typically from Quantum Chromodynamics (QCD). The calculation of these corrections in the high energy regime is described by perturbation theory. In the present study, multi-loop calculations in QCD, including in particular two-loop corrections for single top quark production, are considered. There are several phenomenological motivations to study single top quark production: Firstly, the process is sensitive to the electroweak Wtb-vertex; moreover, non-standard couplings can hint at physics beyond the Standard Model. Secondly, the t-channel cross section measurement provides information on the b-quark Parton Distribution Functions (PDF). Finally, single top quark production enables us to directly measure the Cabibbo-Kobayashi-Maskawa(CKM) matrix element Vtb. The next-to-next-to-leading-order (NNLO) calculation of the single top quark production has many building blocks. In this study, two blocks will be presented: one-loop corrections squared and two-loop corrections interfered with Born. Initially, the one-loop squared contribution at NNLO for single top quark production will be calculated. Before we begin with the calculation of the two-loop corrections to single top quark production, we calculate the QCD form factors of heavy quarks at NNLO, along with the axial vector coupling as a first independent check. A comparison with the relevant literature suggests that this approach is in line with generally accepted procedure. This consistency check provides a proof of the validity of our setup. In the next step, the two-loop corrections to single top quark production will be calculated. After reducing all occurring tensor integrals to scalar integrals, we apply the integration by parts method (IBP) to find the master integrals. This step is a major challenge compared to all similar calculations because of the number of variables in the problem (two Mandelstam variables s and t, the dimension d and the mass of the top quark mt as well as the mass of the W boson mw). Finally, the calculation of the three kinds of topologies – vertex corrections, double boxes and non-planar double boxes – in the two-loop contribution at NNLO calculation will be presented.

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.

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.

Download or read book Shifting Standards written by Allan Franklin and published by University of Pittsburgh Press. This book was released on 2018-11-24 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Shifting Standards, Allan Franklin provides an overview of notable experiments in particle physics. Using papers published in Physical Review, the journal of the American Physical Society, as his basis, Franklin details the experiments themselves, their data collection, the events witnessed, and the interpretation of results. From these papers, he distills the dramatic changes to particle physics experimentation from 1894 through 2009. Franklin develops a framework for his analysis, viewing each example according to exclusion and selection of data; possible experimenter bias; details of the experimental apparatus; size of the data set, apparatus, and number of authors; rates of data taking along with analysis and reduction; distinction between ideal and actual experiments; historical accounts of previous experiments; and personal comments and style. From Millikan's tabletop oil-drop experiment to the Compact Muon Solenoid apparatus measuring approximately 4,000 cubic meters (not including accelerators) and employing over 2,000 authors, Franklin's study follows the decade-by-decade evolution of scale and standards in particle physics experimentation. As he shows, where once there were only one or two collaborators, now it literally takes a village. Similar changes are seen in data collection: in 1909 Millikan's data set took 175 oil drops, of which he used 23 to determine the value of e, the charge of the electron; in contrast, the 1988-1992 E791 experiment using the Collider Detector at Fermilab, investigating the hadroproduction of charm quarks, recorded 20 billion events. As we also see, data collection took a quantum leap in the 1950s with the use of computers. Events are now recorded at rates as of a few hundred per second, and analysis rates have progressed similarly. Employing his epistemology of experimentation, Franklin deconstructs each example to view the arguments offered and the correctness of the results. Overall, he finds that despite the metamorphosis of the process, the role of experimentation has remained remarkably consistent through the years: to test theories and provide factual basis for scientific knowledge, to encourage new theories, and to reveal new phenomenon.

Download or read book Search for Single top quark Production in Pp Collisions at square Root of Strange Quark written by Sarah Kristina Wolinski and published by . This book was released on 2002 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Measurement of the Top Quark Mass Using Single Top Quark Events in Proton proton Collisions at sqrt s written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the top quark mass is reported in events containing a single top quark produced via the electroweak t channel. The analysis is performed using data from proton-proton collisions collected with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The top quark is reconstructed from its decay to a W boson and a b quark, with the W boson decaying leptonically to a muon and a neutrino. The specific topology and kinematic properties of single top quark events in the t channel are used to enhance the purity of the sample, suppressing the contribution from top quark pair production. A fit to the invariant mass distribution of reconstructed top quark candidates yields a value of the top quark mass of 172.95 +/- 0.77 (stat) +0.97/-0.93 (syst) GeV. This result is in agreement with the current world average, and represents the first measurement of the top quark mass in event topologies not dominated by top quark pair production.

Download or read book 91 High Energy Hadronic Interactions written by J. Thanh Van Tran and published by Atlantica Séguier Frontières. This book was released on 1991 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Most Unexpected At Lhc And The Status Of High Energy Frontier The Proceedings Of The International School Of Subnuclear Physics written by Antonino Zichichi and published by World Scientific. This book was released on 2011-12-28 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents:Hot Theoretical Topics:Ultraviolet Behavior of N = 8 Supergravity (L J Dixon)Is the Best Superstring Model NP Complete? (M R Douglas)Erice Lecture on Microscopic Gravity (G Dvali) Supergravity: Foundations and Applications (S Ferrara)Orienfold String Vacua and Strings at the LHC (D Luest)Seminars on Specialized Topics:Status of Dark Matter and Neutrino Physics (A Bettini)Experimental Evidence for Pointlike Baryons at q2 = 4MB2 (S Pacetti) Neutrino Masses, Dark Matter, Baryon Asymmetry and Inflation can be Explained at Once (M Shaposhnikov)Results from RHIC with Implications for LHC (M J Tannenbaum)Quantum Gravity without Space-Time Singularities or Horizons (G 't Hooft)Diffraction in Deep Inelastic Electron Proton Scattering at HERA (G Wolf)The Lesson Needed for the Future (A Zichichi)Highlights from Laboratories:Highlights from Relativistic Heavy Ion Collider (P R Sorensen)The LHC and Beyond — The Energy Frontier (R D Heuer)Highlights from the Gran Sasso Underground Laboratory (E Coccia)Highlights from Fermilab (S J Parke)Special Sessions for New Talents:Radiation Damage Studies for Silicon Sensors for the XFEL (H Perrey)Notes on Chern–Simons Theory in the Temporal Gauge (A Smirnov)Dark Matter via Many Copies of the Standard Model (A Vikman) Readership: Students, researchers and academics in the field of subnuclear physics. Keywords:Black Holes;QCD;SUSY;QED;Collider;Attractors

Download or read book The Most Unexpected at LHC and the Status of High Energy Frontier written by Antonino Zichichi and published by World Scientific. This book was released on 2011 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents: Hot Theoretical Topics: Ultraviolet Behavior of N=8 Supergravity (L J Dixon); Is the Best Superstring Model NP Complete? (M R Douglas); Erice Lecture on Microscopic Gravity (G Dvali); Supergravity: Foundations and Applications (S Ferrara); Orienfold String Vacua and Strings at the LHC (D Luest); Seminar on Specialized Topics: Status of Dark Matter and Neutrino Physics (A Bettini); Experimental Evidence for Pointlike Baryons at q2 = 4MB2 (S Pacetti); Neutrino Masses, Dark Matter, Baryon Asymmetry and Inflation can be Explained at Once (M Shaposhnikov); Results from RHIC with Implications for LHC (M J Tannenbaum); Quantum Gravity without Space-Time Singularities or Horizons (G ''t Hooft); Diffraction in Deep Inelastic Electron Proton Scattering at HERA (G Wolf); The Lesson Needed for the Future (A Zichichi); Highlights from Laboratories: Highlights from RHIC (P R Sorensen); The LHC and Beyond OCo The Energy Frontier (R D Heuer); Highlights from the Gran Sasso Underground Laboratory (E Coccia); Highlights from Fermilab (S J Parke); Special Sessions for New Talents: Radiation Damage Studies for Silicon Sensors for the XFEL (H Perrey); Notes on ChernOCoSimons Theory in the Temporal Gauge (A Smirnov); Dark Matter via Many Copies of the Standard Model (A Vikman).

Download or read book Search for Flavor Changing Neutral Current Top Quark Decays t Hq with H bb in pp Collisions at s 8 TeV with the ATLAS Detector written by Shota Tsiskaridze and published by Springer. This book was released on 2017-08-02 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Higgs Properties at the LHC written by Jason Tsz Shing Yue and published by Springer. This book was released on 2017-08-29 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis studies the properties of the Higgs particle, discovered at the Large Hadron Collider (LHC) in 2012, in order to elucidate its role in electroweak symmetry breaking and cosmological phase transition in the early universe. It shows that a generic spin-2 Higgs impostor is excluded by the precision measurements of electroweak observables and perturbative unitarity considerations. It obtains LHC constraints on anomalous CP-violating Higgs-Top Yukawa couplings and examines the prospects of their measurement in future experiments. Lastly, it discusses in detail the electroweak phase transition and generation of cosmological matter–antimatter asymmetry in the universe with anomalous Higgs couplings.

Download or read book Particle Physics And Cosmology The Quest For Physics Beyond The Standard Model s Tasi 2002 written by Howard E Haber and published by World Scientific. This book was released on 2004-09-13 with total page 913 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the lecture courses conducted at the School of the Theoretical Advanced Study Institute (TASI, Colorado, USA) on Elementary Particle Physics in 2002. In this School, three series of lectures are presented in parallel in the area of phenomenology, TeV-scale physics, and astroparticles physics. The phenomenology lecture series covered a broad spectrum of standard research techniques used to interpret present day and future collider data. The TeV-scale physics lecture series focused on modern speculations about physics beyond the Standard Model, with an emphasis on supersymmetry and extra-dimensional theories. The lecture series on astroparticle physics treated recent developments in theories of dark matter and dark energy, the cosmic microwave background, and prospects for the upcoming era of gravitational wave astronomy.

Download or read book The Higgs Boson Produced With Top Quarks in Fully Hadronic Signatures written by Daniel Salerno and published by Springer Nature. This book was released on 2019-10-25 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this PhD dissertation is the first search at CMS for Higgs bosons produced in association with top quarks (ttH) in a final state consisting of only jets. The results presented in this book uncover a new class of ttH events that will help us elucidate our understanding of the Yukawa sector interactions between the Higgs boson and the top quark. Despite this being the most common decay signature for ttH, a large contamination of SM backgrounds makes it the most challenging for extracting a signal from data. The PhD thesis presents many sophisticated tools and techniques that were developed in order to overcome these challenges. These tools pave the way for future analyses to investigate other standard model and beyond-standard model physics.

Download or read book The Evidence for the Top Quark written by Kent W. Staley and published by Cambridge University Press. This book was released on 2004-04-05 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Evidence for the Top Quark offers both a historical and philosophical perspective on an important recent discovery in particle physics: the first evidence for the elementary particle known as the top quark. Drawing on published reports, oral histories, and internal documents from the large collaboration that performed the experiment, Kent Staley explores in detail the controversies and politics that surrounded this major scientific result.At the same time the book seeks to defend an objective theory of scientific evidence based on error probabilities.