A Study of W Decay Charge Asymmetry Using Hadronic Tau Decays in Proton-antiproton Collisions at [square Root] S PDF Download

Author: Edward William Kuns
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ISBN:
Category :
Languages : en
Pages : 412

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Author:
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Category :
Languages : en
Pages : 5

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This dissertation presents a measurement of the tau charge asymmetry in events where the taus are produced by W decays. This charge asymmetry appears as different rapidity distributions for positive and negative taus. Two competing effects generate tau charge asymmetry. The production mechanism for the W gauge boson generates a charge asymmetry which is a function of the ratio of parton distribution functions, d(x)=u(x), measured at x (almost equal to) M{sub W}/(square root)s. This is the dominant effect for tau charge asymmetry at small rapidity. At higher rapidity, however, the competing charge asymmetry from parity violation in W decay to taus becomes dominant. This tau asymmetry measurement is consistent with the Standard Model with a x2 per degree of freedom equal to 2.5 for 4 degrees of freedom when the asymmetry measurement is folded about y = 0, taking advantage of the CP symmetry of the underlying physics, and 8.9 for 8 degrees of freedom when it is not. This measurement introduces some methods and variables of interest to future analyses using hadronic decay modes of taus. This work was done using the CDF detector in {bar p}p collisions at (square root) = 1.8 TeV at Fermilab's Tevatron accelerator.

Author:
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ISBN:
Category :
Languages : en
Pages : 222

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This dissertation presents a measurement of the tau charge asymmetry in events where the taus are produced by W decays. This charge asymmetry appears as different rapidity distributions for positive and negative taus. Two competing effects generate tau charge asymmetry. The production mechanism for the W gauge boson generates a charge asymmetry which is a function of the ratio of parton distribution functions, d(x)=u(x), measured at x ̃MW/√s. This is the dominant effect for tau charge asymmetry at small rapidity. At higher rapidity, however, the competing charge asymmetry from parity violation in W decay to taus becomes dominant. This tau asymmetry measurement is consistent with the Standard Model with a x2 per degree of freedom equal to 2.5 for 4 degrees of freedom when the asymmetry measurement is folded about y = 0, taking advantage of the CP symmetry of the underlying physics, and 8.9 for 8 degrees of freedom when it is not. This measurement introduces some methods and variables of interest to future analyses using hadronic decay modes of taus. This work was done using the CDF detector in $ar{p}$p collisions at √s = 1.8 TeV at Fermilab's Tevatron accelerator.

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Category : Aeronautics
Languages : en
Pages : 704

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Category :
Languages : en
Pages : 10

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A measurement is described of the charge asymmetry in the pseudorapidity distribution of muons from W boson decay in proton- antiproton collisions at (square root)s = 1.8 TeV using the D0 detector. We also report on a search for extra gauge bosons in the electron decay channel. Mass limits of M{sub W}(prime)> 600 GeV and M{sub Z}(prime)> 440 GeV are obtained at 95% confidence level under the assumption of standard model couplings.

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Category : Power resources
Languages : en
Pages : 998

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Category :
Languages : en
Pages : 0

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This thesis describes a study of the tau-pair final state in proton collisions at a center of mass energy of 7 TeV using the CMS Experiment at the CERN Large Hadron Collider. Tau leptons usually decay to hadrons and their efficient detection is very challenging in a hadronic environment. A novel tau reconstruction algorithm that maintains tau detection efficiency for low background rates was developed. Events were then selected from the CMS 2011 data sample in three T T final states depending on the tau decays: mu + T (h), e+ T (h), e+mu where T (h) denotes a hadronic tau decay. Those events were used to measure the Z-boson production cross section where Z yields T T . A search for the Standard Model and Minimal Supersymmetric Standard Model (MSSM) Higgs bosons was also performed. No signal was observed in the Higgs search and stringent new bounds were set for the SM Higgs production and in the MSSM parameter space.

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Category :
Languages : en
Pages : 11

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A report is given of a search for tau decays of the W boson in p{bar p} collisions at (square root)s = 1.8 TeV using the Collider Detector at Fermilab (CDF). A description of a hardware trigger specifically designed to enhance the number of events with tau decays is presented along with the results of a preliminary analysis of data taken during the 1988--89 run of CDF. 10 refs., 4 figs.

Author: Thomas Kevin Westhusing
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ISBN:
Category :
Languages : en
Pages : 212

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Author: Michail Bachtis
Publisher: Springer
ISBN: 9783319032566
Category : Science
Languages : en
Pages : 152

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The work presented in this thesis spans a wide range of experimental particle physics subjects, starting from level-1 trigger electronics to the final results of the search for Higgs boson decay and to tau lepton pairs. The thesis describes an innovative reconstruction algorithm for tau decays and details how it was instrumental in providing a measurement of Z decay to tau lepton pairs. The reliability of the analysis is fully established by this measurement before the Higgs boson decay to tau lepton pairs is considered. The work described here continues to serve as a model for analysing CMS Higgs to tau leptons measurements.