Download or read book Measurement of the Ttbar Production Cross Section in the MET 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{bar t} --> E{sub T} + jets decay channel by means of neural network tools in proton antiproton collisions at (square root)s = 1.96 TeV recorded by the Collider Detector at Fermilab (CDF). At the Tevatron p{bar 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{bar 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{bar t} production cross section measurement which uses data collected by a 'multijet' trigger, and selects this kind of top decays by requiring a high-P{sub T} 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{bar p} collisions at the center-of-mass energy of (square root)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{bar t} --> E{sub T} + 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 Ttbar Production Cross Section at S 1 2 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the t[bar t] production cross section in the lepton+jets channels with the D0 detector at [radical]s = 1.96 TeV using the lifetime-tagging techniques is presented. The t[bar t] cross section is estimated from the combination of the e+jets and [mu]+jets channels. The obtained result [sigma][sub tt][sup -] = 7.47 [sub -1.14][sup +1.22](stat)[sub -1.03][sup +1.65](syst) [+-] 0.49 (lumi) pb is consistent with the Standard Model expectation.
Download or read book Measurement of the Tt bar Production Cross Section in the Dilepton Channel at CDF written by Reda Tafirout and published by . This book was released on 2004 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a measurement of the t{bar t} production cross section using dilepton events with jets and missing transverse energy in p{bar p}collisions at {radical}s = 1.96 TeV. Using 197 pb{sup -1} of data recorded by the upgraded Collider Detector at Fermilab (CDF II), we use two complementary techniques to select candidate events. The combined result yields a t{bar t} production cross section of 7.0{sub -2.1}{sup +2.4}(stat){sub -1.1}{sup +1.6}(syst) {+-} 0.4(luminosity)pb which is consistent with the Standard Model.
Download or read book Measurement of the Ttbar Production Cross Section in the All jets Final State in Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cross section for tt production in the all-jets final state is measured in pp collisions at a centre-of-mass energy of 8 TeV at the LHC with the CMS detector, in data corresponding to an integrated luminosity of 18.4 fb-1. The inclusive cross section is found to be 275.6 ±6.1 (stat) ± 37.8 (syst) ± 7.2 (lumi) pb. The normalized differential cross sections are measured as a function of the top quark transverse momenta, pT, and compared to predictions from quantum chromodynamics. The results are reported at detector, parton, and particle levels. In all cases, the measured top quark pT spectra are significantly softer than theoretical predictions.
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 Measurement of the Ttbar Interaction Cross Section in the Tau jets Decay Channel Via Multivariable Template Fitting of 4 6 Fb 1 of Data Collected at s written by William P. Edson and published by . This book was released on 2014 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Measurement of the T tbar Production Cross Section in the CDF Detector written by Jose Enrique Palencia Cortezón and published by . This book was released on 2013-11-16 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of TTbar Cross Sections in the Muon jets Final State in Pp Collisions at 13 TeV written by Andre Schmalfeld and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the T bar T Production Cross Section at the Tevatron written by and published by . This book was released on 1997 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the measurement of the t{anti t} production cross section obtained by CDF and D0 experiments with p{anti p} collisions at √s=1. 8 TeV. The analyses presented here refer to ∫ Ldt ≈11O pb−1 collected at the Fermilab Tevatron collider during the run 1992-96. About 85% of the possible t{anti t} decays have been studied in different channels classified according to the number of high P{sub T} leptons found in the final state. The production cross section has been measured in each individual channel and then combined into a single value for each experiment, which is [sigma]{sub tt} = 7.5{sup 1.9}{sub 1.6} pb for CDF and [sigma]{sub tt} = 5.77 ± 1.76 pb for D0.
Download or read book 10th Conference on the Intersections of Particle and Nuclear Physics written by Marvin L. Marshak and published by American Institute of Physics. This book was released on 2010-01-11 with total page 1010 pages. Available in PDF, EPUB and Kindle. Book excerpt: CIPANP 2009 explores areas of common interest between nuclear physicists, high energy (particle) physicists and astrophysicists. These areas range from studies of the strong interactions that bind nuclei together to physics of the very early Universe and include such topics as neutrinos, hadron physics, spin physics, heavy ion physics, QCD and heavy flavor physics. The Conference papers include descriptions of searches for "new physics", phenomena that cannot be accounted for by current theories.
Download or read book Measurement of the T Anti t Production Cross section at S 1 2 written by Alexander Khanov and published by . This book was released on 2004 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the t{bar t} production cross section in the lepton+jets channels with the D0 detector at {radical}s = 1.96 TeV using the lifetime-tagging techniques is presented. The t{bar t} cross section is estimated from the combination of the e+jets and {mu}+jets channels. The obtained result {sigma}{sub t{bar t}} = 7.47{sub -1.14}{sup +1.22}(stat){sub -1.03}{sup +1.65}(syst) {+-} 0.49(lumi) pb is consistent with the Standard Model expectation.
Download or read book Measurement of the T Tbar Production Cross Section at written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the results from the analyses of[ital t][ital[anti t]] decays in[ital dilepton] and[ital lepton+jets] modes with[approx]100 pb[sup -1] of[ital p][ital[anti p]] Collider data at[radical]s= 1.8 TeV collected by the D[null] experiment at the Fermilab Tevatron. We have observed 37[ital t][ital[anti t]] candidate events while the estimated background is 13.4[+-] 3.0 events. The[ital t][ital[anti t]] production cross section has been measured to be 5.2[+-] 1.8 pb at a top quark mass of 170 GeV/c[sup 2].
Download or read book Measurement of the ZZ Production Cross Section Using the Full CDF II Data Set written by and published by . This book was released on 2014 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the t bar t Production Cross Section in the Dilepton Channel in Pp Collisions at sqrt s written by and published by . This book was released on 2013 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Particle Physics Reference Library written by Herwig Schopper and published by Springer Nature. This book was released on 2020 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first open access volume of the handbook series contains articles on the standard model of particle physics, both from the theoretical and experimental perspective. It also covers related topics, such as heavy-ion physics, neutrino physics and searches for new physics beyond the standard model. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A, B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access
Download or read book Discovery Of The Higgs Boson written by Aleandro Nisati and published by World Scientific. This book was released on 2016-08-26 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent observation of the Higgs boson has been hailed as the scientific discovery of the century and led to the 2013 Nobel Prize in physics. This book describes the detailed science behind the decades-long search for this elusive particle at the Large Electron Positron Collider at CERN and at the Tevatron at Fermilab and its subsequent discovery and characterization at the Large Hadron Collider at CERN. Written by physicists who played leading roles in this epic search and discovery, this book is an authoritative and pedagogical exposition of the portrait of the Higgs boson that has emerged from a large number of experimental measurements. As the first of its kind, this book should be of interest to graduate students and researchers in particle physics.
