971 research outputs found

    Top Quark Properties at the TeVatron

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    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^{-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^{-1} and 4.8 fb−1^{-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.Comment: 6 pages, Presented at the 2010 Rencontres de Moriond EW, La Thuile, Aosta Valley, Italy, 06-13 Mar 201

    Beyond the Standard Model searches with top quarks at D0

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    Due to its high mass and short lifetime, the top quark plays an important role in checking the Standard Model of particle physics. In this report, we pr\ esent a variety of searches for physics beyond the Standard Model, involving top quarks, at the D0 detector at the Fermilab Tevatron collider. Specifically, we present searches in top quark pair production, single top quark production and top quark decays. The search spectra discussed here involve a search for ttˉt\bar{t} resonances, associated production of Higgs bosons and ttˉt\bar{t}, charged Higgs bosons and heavy gauge W′W^{'} bosons. Furthermore, we measure the forward-backward charge asymmetry and a ratio of branching fractions.Comment: To appear in the proceedings of 2009 Europhysics Conference on High Energy Physics: HEP 2009 (EPS-HEP 2009), Cracow, Poland, 16-22 Jul 2009. 5 pages, 2 figures

    Top Quark Properties

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    Since its discovery in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron collider, the top quark has undergone intensive studies. Besides the Tevatron experiments, with the start of the LHC in 2010 a top quark factory started its operation. It is now possible to measure top quark properties simultaneously at four different experiments, namely ATLAS and CMS at LHC and CDF and D0 at Tevatron. Having collected thousands of top quarks each, several top quark properties have been measured precisely, while others are being measured for the first time. In this article, recent measurements of top quark properties from ATLAS, CDF, CMS and D0 are presented, using up to 5.4 fb-1 of integrated luminosity at the Tevatron and 1.1 fb^-1 at the LHC. In particular, measurements of the top quark mass, mass difference, forward backward charge asymmetry, tt - spin correlations, the ratio of branching fractions, W helicity, anomalous couplings, color flow and the search for flavor changing neutral currents are discussed.Comment: 8 pages, 1 figure, proceedings for the PIC2011 conference, Vancouver, BC, Canad

    Top Quark Mass Measurements at the Tevatron

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    Since the discovery of the top quark in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron proton antiproton collider, precise measurements of its mass are ongoing. Using data recorded by the D0 and CDF experiment, corresponding to up to the full Tevatron data sample, top quark mass measurements performed in different final states using various extraction techniques are presented in this article. The recent Tevatron top quark mass combination yields m_t=173.20 +-0.87 GeV. Furthermore, measurements of the top antitop quark mass difference from the Tevatron are discussed.Comment: 6 pages, 2 figures, presented at EPS-HEP 2013, Stockholm, Sweden, July 18-24, 201

    Tevatron Top-Quark Combinations and World Top-Quark Mass Combination

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    Almost 20 years after its discovery, the top quark is still an interesting particle, undergoing precise investigation of its properties. For many years, the Tevatron proton antiproton collider at Fermilab was the only place to study top quarks in detail, while with the recent start of the LHC proton proton collider a top quark factory has opened. An important ingredient for the full understanding of the top quark is the combination of measurements from the individual experiments. In particular, the Tevaton combinations of single top-quark cross sections, the ttbar production cross section, the W helicity in top-quark decays as well as the Tevatron and the world combination of the top-quark mass are discussed.Comment: 5 pages, 2 figures, to appear in the proceedings of Top2014, Cannes, France (28th Sept - 3rd Oct 2014

    V+jets Background and Systematic Uncertainties in Top Quark Analyses

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    Vector boson production in association with jets is an important process to test perturbative quantum chromodynamics and also a background process in top quark analyses. Measurements on vector boson production in association with light and heavy flavour jets are presented, performed by the D0 and CDF collaborations at the Tevatron as well as the ATLAS and CMS experiments at LHC. Techniques applied in top quark analyses to estimate the vector boson+jets background are also discussed.Comment: 10 pages, 4 figures; Proceedings of the 6th International Workshop on Top Quark Physics (TOP13), Durbach, Germany, September 14-19, 201
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