Author: Johnny Shing Tung Ng
Publisher:
ISBN:
Category : Z bosons
Languages : en
Pages : 286

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Author: Mika Vesterinen
Publisher: Springer Science & Business Media
ISBN: 3642307884
Category : Science
Languages : en
Pages : 226

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This work develops novel data analysis techniques enabling aspects of the Standard Model of particle physics to be tested with unprecedented precision using data from the DZero experiment at the high energy “Tevatron” proton-antiproton collider at Fermilab, Chicago. Vesterinen's measurements of the transverse momentum of Z bosons using the novel variable φ* have exposed deficiencies in the current state-of-the-art theoretical predictions for vector boson production at hadron colliders. These techniques are now being used in the experiments at CERN’s Large Hadron Collider (LHC) and have stimulated considerable interest in the theoretical particle physics community. Furthermore, Vesterinen's measurements of the cross sections for the production of pairs of vector bosons (WZ and ZZ) are to date the most precise ever made.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 264

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Two analyses are performed with the large samples of dielectron and dimuon events collected by the D0 experiment at the Fermilab Tevatron $p\bar{p}$ collider. The dilepton transverse momentum ($p_T$) distribution in $Z/\gamma^* → \ell^+\ell^-$ production is a powerful probe of Quantum chromodynamics. Until now, this distribution has been measured with limited precision. An alternative variable, $\phi^*_\eta$, is proposed due to its relatively low susceptibility to detector effects. The $\phi^*_\eta$, distribution of events with $Z/\gamma^* → \ell^+\ell^-$ invariant masses between 70 and 110 GeV, is measured in three bins of dilepton rapidity. This measurement, with 7.3 fb$^{-1}$ of data, is significantly more precise than previous measurements of the $p_T$ distribution. A state-of-the-art QCD Monte Carlo program is in modest agreement with the data. Using 8.6 fb$^{-1}$ of data, the $ZZ/\gamma^* → \nu\bar{\nu}\ell^+\ell^-$ and $WZ/\gamma^* → \ell\nu\ell^+\ell^-$ processes are studied, yielding production cross sections of, $\sigma(p\bar{p} \rightarrow ZZ/\gamma^*)$ = 1.64 $\pm$ 0.46 p b and $\sigma(p\bar{p} \rightarrow WZ/\gamma^*)$ = 4.46 $\pm$ 0.64 pb, for $Z/\gamma^* → \ell^+\ell^-$ invariant masses between 60 and 130 GeV. These are in agreement with Standard Model predictions.

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ISBN:
Category :
Languages : en
Pages :

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We present recent results on measurements of the transverse momentum distribution of W and Z bosons, the angular distribution of electrons from W decays, and on color coherence effects in W+jets events from p{bar p} collisions at (square root)s = 1.8 TeV at the Fermilab Tevatron Collider. The data are compared to perturbative QCD calculations.

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ISBN:
Category :
Languages : en
Pages : 12

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Using 7.3 fb−1 of p{bar p} collisions collected by the D0 detector at the Fermilab Tevatron, we measure the distribution of the variable [phi]*{sub {eta}}, which probes the same physical effects as the Z/[gamma]* boson transverse momentum, but is less susceptible to the effects of experimental resolution and efficiency. A QCD prediction is found to describe the general features of the [phi]*{sub {eta}} distribution, but is unable to describe its detailed shape or dependence on boson rapidity. A prediction that includes a broadening of transverse momentum for small values of the parton momentum fraction is strongly disfavored.

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Category :
Languages : en
Pages :

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We present measurements of the forward-backward asymmetry (A_fb) in dilepton pair decays of Z bosons produced in ppbar collisions using the full Tevatron dataset. The CDF experiment extracts a value for the effective weak mixing angle parameter sin^{2}\theta^{l}_{eff} of 0.2315 +/- 0.0010 from the A_fb distribution of dimuon events in 9.2 fb^{-1} of integrated luminosity. From dielectron events in 9.7 fb^{-1} of data, the D0 experiment finds sin^{2}\theta^{l}_{eff} = 0.23106 +/- 0.00053, the world's most precise measurement of sin^{2}\theta^{l}_{eff} from hadron colliders and with light quark couplings.

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Category :
Languages : en
Pages : 179

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This thesis is a description of the measurement of the W boson mass using the D0 Run II detector with 770 pb−1 of p{bar p} collision data. These collisions were produced by the Tevatron at √s = 1.96 TeV between 2002 and 2006. We use a sample of W → e[nu] and Z → ee decays to determine the W boson mass with the transverse momentum distribution of the electron and the transverse mass distribution of the boson. We measure M{sub W} = XXXXX ± 37 (stat.) ± 26 (sys. theo.) ± 51 (sys. exp.) MeV = XXXXX ± 68 MeV with the transverse momentum distribution of the electron and M{sub W} = XXXXX ± 28 (stat.) ± 17 (sys. theo.) ± 51 (sys. exp.) MeV = XXXXX ± 61 MeV with the transverse mass distribution.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 13

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The transverse momentum distributions of W and Z bosons produced in p{anti p} collisions at (square root)s = 1.8 TeV are measured with the D0 detector at Fermilab. The results are compared to QCD calculations which include soft gluon resummation. The transverse momentum distribution of the Z boson is consistent with the calculation of Ladinsky and Yuan, and is used to extract their non-perturbative parameter 92-

Author: Eric Michael Flattum
Publisher:
ISBN:
Category : Proton-antiproton interactions
Languages : en
Pages : 368

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8

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