Measurements of Inclusive W and Z Cross Sections in Pp Collisions at Sqrt(s)

Measurements of Inclusive W and Z Cross Sections in Pp Collisions at Sqrt(s)
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Total Pages : 38
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ISBN-10 : OCLC:1066555989
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Rating : 4/5 (89 Downloads)

Synopsis Measurements of Inclusive W and Z Cross Sections in Pp Collisions at Sqrt(s) by :

Measurements of inclusive W and Z boson production cross sections in pp collisions at sqrt(s)=7 TeV are presented, based on 2.9 inverse picobarns of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give sigma(pp to WX) times B(W to muon or electron + neutrino) = 9.95 \pm 0.07(stat.) \pm 0.28(syst.) \pm 1.09(lumi.) nb and sigma(pp to ZX) times B(Z to oppositely charged muon or electron pairs) = 0.931 \pm 0.026(stat.) \pm 0.023(syst.) \pm 0.102(lumi.) nb. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported.

Measurement of W-gamma and Z-gamma Production in Pp Collisions at Sqrt(s)

Measurement of W-gamma and Z-gamma Production in Pp Collisions at Sqrt(s)
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Total Pages : 32
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ISBN-10 : OCLC:1066549646
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Rating : 4/5 (46 Downloads)

Synopsis Measurement of W-gamma and Z-gamma Production in Pp Collisions at Sqrt(s) by :

A measurement of W-gamma and Z-gamma production in proton-proton collisions at sqrt(s) = 7 TeV is presented. Results are based on a data sample recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 36 inverse picobarns. The electron and muon decay channels of the W and Z are used. The total cross sections are measured for photon transverse energy>10 GeV and spatial separation from charged leptons in the plane of pseudorapidity and azimuthal angle>0.7, and with an additional dilepton invariant mass requirement of> 50 GeV for the Z-gamma process. The following cross section times branching fraction values are found: sigma(pp to W-gamma+X) B(W to lepton neutrino) = 56.3 +/- 5.0 (stat.) +/- 5.0 (syst.) +/- 2.3 (lumi.) pb and sigma(pp to Z-gamma+X) B}(Z to lepton lepton) = 9.4 +/- 1.0 (stat.) +/- 0.6 (syst.) +/- 0.4 (lumi.) pb. These measurements are in agreement with standard model predictions. The first limits on anomalous WW gamma, ZZ gamma, and Z gamma gamma trilinear gauge couplings at sqrt(s) = 7 TeV are set.

$Z+\gamma$ Cross-Section Measurement, $\sigma*BR(Z+\gamma)$, in the Electron Channel for $p\bar{p}$ Collisions at $\sqrt{s}$

$Z+\gamma$ Cross-Section Measurement, $\sigma*BR(Z+\gamma)$, in the Electron Channel for $p\bar{p}$ Collisions at $\sqrt{s}$
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Total Pages : 120
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ISBN-10 : OCLC:982476745
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Rating : 4/5 (45 Downloads)

Synopsis $Z+\gamma$ Cross-Section Measurement, $\sigma*BR(Z+\gamma)$, in the Electron Channel for $p\bar{p}$ Collisions at $\sqrt{s}$ by :

The Z+[gamma] cross-section x branching ratio in the electron channel has been measured using the inclusive Z data sample from the CDF '88-'89 collider run, for which the total integrated luminosity was 4.05 ± 0.28 pb-1.

Wild, gewild, gevild

Wild, gewild, gevild
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Total Pages : 52
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ISBN-10 : OCLC:66076595
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Rating : 4/5 (95 Downloads)

Synopsis Wild, gewild, gevild by :

Measurements of the W and Z Inclusive Cross Sections and Determination of the W Decay Width

Measurements of the W and Z Inclusive Cross Sections and Determination of the W Decay Width
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ISBN-10 : OCLC:68344150
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Rating : 4/5 (50 Downloads)

Synopsis Measurements of the W and Z Inclusive Cross Sections and Determination of the W Decay Width by :

Recent results on the production of W and Z gauge bosons in p[anti p] collisions at[radical]s= 1.8 TeV at the Fermilab Tevatron Collider from the D0 and CDF experiments are reviewed. Measurements of the inclusive cross sections times leptonic branching ratios in both the electron and muon decay channels are summarized and compared to QCD predictions. Using the ratio R=[sigma][sub W][center-dot] B(W[yields] lv)/[sigma][sub Z][center-dot] B(Z[yields] ll) and assuming standard model couplings, an indirect determination of the W decay width is obtained. By comparing this measured value with the predicted value for the W width, a limit on the deviation from the standard model is obtained.

Measurement of the W and Z Cross Sections in the Electron Channel for P Anti-p Collisions at S**(1/2)

Measurement of the W and Z Cross Sections in the Electron Channel for P Anti-p Collisions at S**(1/2)
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Total Pages : 234
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ISBN-10 : OCLC:316307900
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Rating : 4/5 (00 Downloads)

Synopsis Measurement of the W and Z Cross Sections in the Electron Channel for P Anti-p Collisions at S**(1/2) by : John Michael Gardner

This dissertation presents measurements of the inclusive production cross sections for W and Z gauge bosons decaying through the electron channel with p{bar p} collisions at a center-of-mass energy of 1.96 TeV. The ratio of these cross sections is then used to extract the W total width. The Standard Model (SM) of electroweak and strong interactions is a collection of theories which together encompass what is currently known about the elementary particles that make up matter and the forces through which they interact. Experimentalists are constantly searching for violations of the Standard Model by making precision measurements of predicted interactions. The decay of the W boson is one such interaction. The rate of its decay is reflected in its width which is predicted to high precision using Standard Model-based calculations. Therefore, a high precision experimental width measurement would be very sensitive to any such violation. In principle the W and Z boson production cross sections could also be good Standard Model tests. However, a precise knowledge of integrated luminosity is required which is unfortunately difficult to obtain at the Tevatron. In fact, the W and Z cross section results can be used to obtain a more precise luminosity measurement. The data set consists of a total integrated luminosity of 177 pb{sup -1} collected from September 2002 to September 2003 using the D0 detector at Fermilab.

Z +? Cross-section Measurement,?*BR(Z +?), in the Electron Channel for P{bar P} Collisions at √s

Z +? Cross-section Measurement,?*BR(Z +?), in the Electron Channel for P{bar P} Collisions at √s
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Total Pages : 109
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ISBN-10 : OCLC:1061322681
ISBN-13 :
Rating : 4/5 (81 Downloads)

Synopsis Z +? Cross-section Measurement,?*BR(Z +?), in the Electron Channel for P{bar P} Collisions at √s by :

The Z +? cross-section x branching ratio in the electron channel has been measured using the inclusive Z data sample from the CDF 1988--1989 collider run, for which the total integrated luminosity was 4.05 ± 0.28 pb−1. Two Z? candidates are observed from central photon events with?R/{sub?}> 0.7 and E{sub t}{sup?}> 5.0 GeV. From these events the? * BR(Z +?) is measured and compared with SM predictions:? * BR(Z +?){sub e} = 6.8{sub -5.7}{sup +5.7}(stat + syst)pb? * BR(Z + {gamma})SM = 4.7{sub -4.7}{sup +0.7}(stat + syst)pb. From this ZZ{sub {gamma}} cross section measurement limits on the Z{sub {gamma}{gamma}} and couplings for three different choices of compositeness scale?{sub Z} are obtained. The experimental sensitivity to the h30{sup Z, {gamma}}/h10{sup Z, {gamma}} couplings is in the range of?{sub Z} - 450--500 GeV and for the h40{sup Z{gamma}}/h20{sup Z, {gamma}} couplings?{sub Z} - 300 GeV.