Download or read book Measurements of Top Quark Production and Properties at the Tevatron written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this letter, we summarize the latest results of the top-quark production and properties at the Tevatron. We do not include results of the top-quark mass and single top-quark production as they were presented in separate talks. The results of the measurements are mostly consistent with the standard-model predictions. However, by looking at the production asymmetry measured by CDF, one can see a discrepancy in both, $t\bar{t}$ inclusive and lepton-based measurements. D\O\ results of production asymmetry are compatible with the standard-model predictions as well as with the CDF results.
Download or read book Adams After Noon Press Clippings written by and published by . This book was released on 19?? with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Top Quark Pair Production and Properties Measurements at the Tevatron written by and published by . This book was released on 2008 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Tevatron proton-antiproton collider at Fermilab with its center of mass energy of 1.96 TeV is currently the only source for the production of top quarks. This report reflects the current status of measurements of the top quark pair production cross section and properties performed by the CDF and D0 Collaborations. Utilizing datasets of up to two fb−1, these measurements allow unprecedented precision in probing the validity of the Standard Model.
Download or read book Measurements of Top Quark Properties at the Tevatron written by and published by . This book was released on 2012 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark is the most recently discovered of the standard model quarks, and studies of its properties are important tests of the standard model. Many measurements of top properties have been produced by the CDF and D0 collaborations, which study top quarks produced in p{bar p} collisions at the Fermilab Tevatron with a center-of-mass energy √s = 1.96 TeV. We describe recent results from top properties measurements at the Tevatron using datasets corresponding to integrated luminosities up to 8.7 fb−1.
Download or read book Measurements of Top Quark Properties at the Tevatron Collider written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The discovery of the top quark in 1995 opened a whole new sector of investigation of the Standard Model; today top quark physics remains a key priority of the Tevatron program. Some of the measurements of top quark properties, for example its mass, will be a long-standing legacy. The recent evidence of an anomalously large charge asymmetry in top quark events suggests that new physics could couple preferably with top quarks. I will summarize this long chapter of particle physics history and discuss the road the top quark is highlighting for the LHC program.
Download or read book Studies of Top Quark Properties at the Tevatron written by and published by . This book was released on 2012 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the recent measurements of the top quark properties in proton antiproton collisions at √s = 1.96 TeV is presented. These measurements are based on 5.4-8.7 fb−1 of data collected with the D0 and CDF experiments at the Fermilab Tevatron collider. The top quark mass and width measurements, studies of the spin correlation in top quark pair production, W boson helicity measurement, searches for anomalous top quark couplings and Lorentz invariance violation are discussed.
Download or read book Top Quark Properties at the TeVatron written by and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discovered in 1995 by CDF and D0 at the Fermilab Tevatron collider, the top quark remains interesting to test the Standard Model. Having collected more than 7 fb−1 of integrated luminosity with both experiments until today, several top quark properties have been measured with increasing precision, while other properties have been investigated for the first time. In this article recent measurements of top quark properties from CDF and D0 are presented, using between 1 fb−1 and 4.8 fb−1 of data. In particular, the measurement of the top quark mass, the top quark width, the top antitop mass difference, a check of the electric charge of the top quark, measurements of the top antitop quark spin correlation and W helicity as well as a search for charged Higgs bosons are discussed.
Download or read book Studies of Top Quark Properties and Search for Electroweak Single Top Quark Production at the Tevatron written by and published by . This book was released on 2007 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark was discovered in 1995 by the CDF and D0 experiments at the Fermilab Tevatron during the Run I operation. Since the start of the Tevatron Run II in 2001, both experiments have collected (almost equal to)2 fb−1 data samples, which are over twenty times larger than that used in the Run 1 discovery. This larger data sample allows more precise studies of top-quark properties; differences between observed top-quark properties and the Standard Model (SM) prediction may give hints to possible physics beyond the SM. Here we present the latest results on the measurements of top-quark properties and the search for electroweak (EW) single top quark production from the CDF and D0 collaborations. The integrated luminosity used for the measurements corresponds to about 1 fb−1.
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.
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 Top Mass Measurements at the Tevatron written by and published by . This book was released on 2012 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: First observed in 1995, the top quark is the third-generation up-type quark of the standard model of particle physics (SM). The CDF and D0 collaborations have analyzed many t{bar t} events produced by the Tevatron collider, studying many properties of the top quark. Among these, the mass of the top quark is a fundamental parameter of the SM, since its value constrains the mass of the yet to be observed Higgs boson. The analyzed events were used to measure the mass of the top quark m{sub t} ≃ 173.2 GeV/c2 with an uncertainty of less than 1 GeV/c2. We report on the latest top mass measurements at the Tevatron, using up to 6 fb−1 of data for each experiment.
Download or read book Top Quark Physics at the Tevatron written by and published by . This book was released on 2010 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors review the field of top-quark physics with an emphasis on experimental techniques. The role of the top quark in the Standard Model of particle physics is summarized and the basic phenomenology of top-quark production and decay is introduced. They discuss how contributions from physics beyond the Standard model could affect the top-quark properties or event samples. The many measurements made at the Fermilab Tevatron, which test the Standard model predictions or probe for direct evidence of new physics using the top-quark event samples, are reviewed here.
Download or read book Top Antitop Quark Production and Decay Properties at the Tevatron written by and published by . This book was released on 2010 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: At the Tevatron, the collider experiments CDF and D0 have data sets at their disposal that comprise a few thousand reconstructed top-antitop-quark pairs and allow for precision measurements of the cross section as well as production and decay properties. Besides comparing the measurements to standard model predictions, these data sets open a window to physics beyond the standard model. Dedicated analyses look for new heavy gauge bosons, fourth generation quarks, and flavor-changing neutral currents. In this mini-review the current status of these measurements is summarized.
Download or read book Measurements of Top Properties at the Tevatron written by and published by . This book was released on 2007 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The large data samples of thousands of top events collected at the Tevatron experiments CDF and D{O} allow for a variety of measurements to analyze the properties of the top quark. Guided by the question ''Is the top quark observed at the Tevatron really the top quark of the standard model, '' we present Tevatron analyses studying the top production mechanism including resonant t{bar t} production, the V -A structure of the t --> Wb decay vertex, the charge of the top quark, and single-top production via flavor-changing neutral currents.
Download or read book Measurement of Top Quark Properties at the Tevatron written by Jessica Leveque and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We highlight the most recent top quark properties measurements performed at the Tevatron collider by the CDF and D0 experiments. The data samples used for the analyses discussed correspond to an integrated luminosity varying from 360 pb{sup -1} to 760 pb{sup -1}.
Download or read book Tevatron Top Physics written by and published by . This book was released on 2009 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: A summary of the most recent results on top quark physics obtained at Fermilab's Tevatron proton-antiproton collider, operating at a centre of mass energy of 1.96 TeV, is presented. Measurements of the top pair and single top quark production cross sections, the investigation of top quark decay properties, the precision measurement of the top quark mass as well as searches for physics beyond the standard model are discussed.
