Download or read book Measurement of the T bar t Production Cross Section in the ET jets Channel at CDF written by and published by . This book was released on 2008 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is focused on an inclusive search of the t$ar{t}$ → ET + jets decay channel by means of neural network tools in proton antiproton collisions at √s = 1.96 TeV recorded by the Collider Detector at Fermilab (CDF). At the Tevatron p$ar{p}$ collider top quarks are mainly produced in pairs through quark-antiquark annihilation and gluon-gluon fusion processes; in the Standard Model description, the top quark then decays to a W boson and a b quark almost 100% of the times, so that its decay signatures are classified according to the W decay modes. When only one W decays leptonically, the t$ar{t}$ event typically contains a charged lepton, missing transverse energy due to the presence of a neutrino escaping from the detector, and four high transverse momentum jets, two of which originate from b quarks. In this thesis we describe a t$ar{t}$ production cross section measurement which uses data collected by a 'multijet' trigger, and selects this kind of top decays by requiring a high-PT neutrino signature and by using an optimized neural network to discriminate top quark pair production from backgrounds. In Chapter 1, a brief review of the Standard Model of particle physics will be discussed, focusing on top quark properties and experimental signatures. In Chapter 2 will be presented an overview of the Tevatron accelerator chain that provides p$ar{p}$ collisions at the center-of-mass energy of √s = 1.96 TeV, and proton and antiproton beams production procedure will be discussed. The CDF detector and its components and subsystems used for the study of p{bar p} collisions provided by the Tevatron will be described in Chapter 3. Chapter 4 will detail the reconstruction procedures used in CDF to detect physical objects exploiting the features of the different detector subsystems. Chapter 5 will provide an overview of the main concepts regarding Artificial Neural Networks, one of the most important tools we will use in the analysis. Chapter 6 will be devoted to the description of the main characteristics of the t$ar{t}$ → ET + jets decay channel used to train our neural network to discriminate the top pair production from background processes. We will discuss the event selection method and the technique used for background prediction, that will rely on b-jets identification rate parameterization. Finally, Chapter 7 will provide a description of the final data sample and a detailed discussion of the systematic uncertainties before determining the cross section measurement by means of a likelihood maximization.
Download or read book Measurement of the T Tbar Cross Section at the Run II Tevatron Using Support Vector Machines written by and published by . This book was released on 2010 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation measures the t{bar t} production cross section at the Run II CDF detector using data from early 2001 through March 2007. The Tevatron at Fermilab is a p{bar p} collider with center of mass energy √s = 1.96 TeV. This data composes a sample with a time-integrated luminosity measured at 2.2 ± 0.1 fb−1. A system of learning machines is developed to recognize t{bar t} events in the 'lepton plus jets' decay channel. Support Vector Machines are described, and their ability to cope with a multi-class discrimination problem is provided. The t{bar t} production cross section is then measured in this framework, and found to be [sigma]{sub t{bar t}} = 7.14 ± 0.25 (stat){sub -0.86}{sup +0.61}(sys) pb.
Download or read book Zhongguo di shao shu min zu he min zu qu yu zi zhi written by Zhengxiang Chen and published by . This book was released on 1972 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Single top Production T channel Cross Section Measurement in the Electron jets Final State at ATLAS with 35 rm Pb 1 of Data written by Gia Khoriauli and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Differential Cross Sections in the Ttbar L jets Channel written by and published by . This book was released on 2009 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The analysis presented in this thesis focuses on kinematic distributions in the t{bar t} system and studies in detail selected differential cross sections of top quarks as well as the reconstructed t{bar t} pair, namely the top quark transverse momentum and the t{bar t} system mass. The structure of the thesis is organized as follows: first the Standard Model of the particle physics is briefly introduced in Chapter 1, with relevant aspects of electroweak and strong interactions discussed. The physics of the top quark and its properties are then outlined in Chapter 2, together with the motivation for measuring the transverse top quark momentum and other kinematic-related variables of the t{bar t} system. The concepts of present-day high energy physics collider experiments and the explicit example of Fermilab Tevatron collider and the D0 detector in Chapters 3 and 4 are followed by the description of basic detector-level objects, i.e. tracks, leptons and jets, in Chapter 5; their identification and calibration following in next chapter with the emphasis on the jet energy scale in Chapter 6 and jet identification at the D0. The analysis itself is outlined in Chapter 7 and is structured so that first the data and simulation samples and the basic preselection are described in Chapter 8 and 9, followed by the kinematic reconstruction part in Chapter 10. Chapter 11 on background normalization and Chapter 12 with raw reconstructed spectra results (at the detector-smeared level) are followed by the purity-based background subtraction method and examples of signal-level corrected spectra in Chapter 13. Next, the procedure of correcting measured spectra for detector effects (unfolding) is described in Chapters 14-15, including migration matrix studies, acceptance correction determination as well as the regularized unfolding procedure itself. Final differential cross sections are presented in Chapter 16 with the main results in Figures 16.19-16.20. Summary and discussion close the main analysis part in Chapter 17, supplemented by appendices on the wealthy of analysis control plots of the t{bar t} → l + jets channel, selected D0 event displays and finally the list of publications and references. Preliminary results of this analysis have been documented in D0 internal notes [UnfoldTop], [p17Top], [p14Top]; as well as presented at conferences [APS08], [APS05]. The author has also been a co-author of more than 135 D0 collaboration publications since 2005. The author has taken part in the jet energy scale calibration efforts performing final closure tests and deriving a correction to jet energy offset due to the suppression of the calorimeter signal. The author has also co-performed the [phi]-intercalibration of the hadronic calorimeter and co-supervised the electromagnetic [phi]-intercalibration; recently has also been involved in maintaining the jet identification efficiencies measurement as a JetID convener. During the years in Fermilab, many events have taken place in the course of the analysis in persuasion, including more than 170 shifts served for the D0 detector with or without the beam, 168 talks presented with mixed results and reactions; and tens of thousands of code lines in C (and sometimes perhaps even really C++) written while terabytes of data were processed, analyzed, and sometimes also lost. It has been a long but profoundly enriching chapter of my life.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the T bar T Cross Section at s written by and published by . This book was released on 2003 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the t{bar t} cross section at √s = 1.96 TeV is carried out on data samples of ≈40 pb−1 in dilepton channels (e?, ee and??) and lepton+jets channels using two complementary approaches: a fully topological analysis and a soft-muon-tag. Overall, 17 events are observed with an expected background of 6.5 ± 0.6. This excess corresponds to an observation probability of three standard deviations and the measured t{bar t} cross section is:?{sub p}{bar p}→ t{bar t} = 8.5{sub -3.6}{sup +4.5} (stat) {sub -3.5}{sup +6.3} (sys) ± 0.8 (lumi) pb.
Download or read book Measurement of the T bar t Cross Section at the Run II Tevatron Using Support Vector Machines written by and published by . This book was released on 2010 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation measures the t$ar{t}$ production cross section at the Run II CDF detector using data from early 2001 through March 2007. The Tevatron at Fermilab is a p$ar{p}$ collider with center of mass energy √s = 1.96 TeV. This data composes a sample with a time-integrated luminosity measured at 2.2 ± 0.1 fb-1. A system of learning machines is developed to recognize t$ar{t}$ events in the 'lepton plus jets' decay channel. Support Vector Machines are described, and their ability to cope with a multi-class discrimination problem is provided. The t$ar{t}$ production cross section is then measured in this framework, and found to be ?t$ar{t}$ = 7.14 ± 0.25 (stat)-0.86+0.61(sys) pb.
Download or read book Measurement of the production cross section ratio top antitop jets to top antitop inclusive in 106 0 4 1 pb 1 of data collected by CDF during Run1A 1B of the Tevatron written by and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Single top Production T channel Cross Section Measurement in the Electron jets Final State at ATLAS with 35 Pb 1 of Data written by and published by . This book was released on 2012 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the T Tbar Production Cross Section at written by and published by . This book was released on 1996 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Top Production Cross Section from CDF written by Anyes Taffard and published by . This book was released on 2004 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent top physics results from the CDF at a center-of-mass energy of 1.96 TeV are presented. Measurements of the t{bar t} production cross section in all three decay channels, using a set of complementary experimental methods, are presented as well as results of a search for single top production.
Download or read book Proceedings Of The 28th International Conference On High Energy Physics In 2 Volumes written by Zygmunt Ajduk and published by World Scientific. This book was released on 1997-04-11 with total page 1878 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 28th conference from the Rochester series was the major high energy physics conference in 1996. Volume one contains short reports on new theoretical and experimental results. Volume two consists of the review talks presented in the plenary sessions.
Download or read book Measurement of the Tt Production Cross section in the Jets Final State at s written by Maria Chiara Conidi and published by . This book was released on 2013 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1989 with total page 992 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cross section Measurement of Single top T channel Production at ATLAS written by Ruth Herrberg-Schubert and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Differential t bar t Production Cross Sections in p bar p Collisions written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
