Measurement of the Inclusive W and Z Production Cross Sections in Pp Collisions at $ \sqrt {s}

Measurement of the Inclusive W and Z Production Cross Sections in Pp Collisions at $ \sqrt {s}
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Release: 2011
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A measurement of inclusive W and Z production cross sections in pp collisions at sqrt(s)=7 TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. The measured inclusive cross sections are sigma(pp-> WX) B(W-> l nu) = 10.30 +/- 0.02 (stat.) +/- 0.10 (syst.) +/- 0.10 (th.) +/- 0.41 (lumi.) nb and sigma(pp -> ZX) B(Z-> l+̂l-̂) = 0.974 +/- 0.007 (stat.) +/- 0.007 (syst.) +/- 0.018 (th.) +/- 0.039 (lumi.) nb, limited to the dilepton invariant mass range 60 to 120 GeV. The luminosity-independent cross section ratios are [sigma(pp->WX) B(W-> l nu)]/[sigma(pp-> ZX) B(Z->l+̂l-̂)] = 10.54 +/- 0.07 (stat.) +/- 0.08 (syst.) +/- 0.16 (th.) and [sigma(pp->W+̂X) B(W+̂ -> l+̂nu)] / [sigma(pp->W-̂ X) B(W-̂ -> l-̂ nu)] = 1.421 +/- 0.006 (stat.) +/- 0.014 (syst.) +/- 0.029 (th.). The measured values agree with next-to-next-to-leading order QCD cross section calculations based on recent parton distribution functions.

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
Release: 2011
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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.

Diboson Production Cross-sections at Square Root S

Diboson Production Cross-sections at Square Root S
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Release: 2004
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Recent results of W[gamma], Z[gamma] and WW cross-section measurements in the electron and muon channels are reported from p[bar p] collisions at [radical]s = 1.96 TeV recorded by the CDF and D0 collaborations. Total cross-sections and kinematic distributions are found to be consistent with Standard Model expectations.

W and Z Production Cross Sections at

W and Z Production Cross Sections at
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Total Pages: 5
Release: 1996
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We present a measurement of the production cross section times branching ratio for {ital W} and {ital Z} bosons decaying to the electrons or muons in {ital p}{ital {anti p}} collisions at (square root)s = 1.8 TeV using data recorded at the Tevatron during the 1994-1995 collider run. Using the ratio of these two measurements, we derive the {ital W} leptonic branching fraction and the width of the {ital W} boson.

A Measurement of W Boson-photon and Z Boson-photon Cross Sections in the Muon Channel in 1.8 TeV Proton-antiproton Collisions

A Measurement of W Boson-photon and Z Boson-photon Cross Sections in the Muon Channel in 1.8 TeV Proton-antiproton Collisions
Author: Christopher B. Luchini
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Release: 1994
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We have measured the production cross sections x decay branching ratios for W + $gamma$ and Z + $gamma$ in the muon channel in $sqrt{s}$ = 1.8 TeV p-p collisions, from 3.54 $pm$ 0.24 $pbsp{-1}$ of muon W and Z data from the CDF 1988-89 Tevatron collider run. For photons in the central region ($vertetavert $ 5.0 GeV and lepton-photon angular separation $Delta Rsb{ellsbgamma} >$ 0.7, 5 $Wsb{gamma}$ candidates and 2 $Zsb{gamma}$ candidates were observed. From these events, the $sigma cdot BR(W + gamma)$ and $sigma cdot BR(Z + gamma)$ cross sections for the muon samples are measured, and compared with Standard Model predictions. We also determined the cross section ratios, $Wsb{gamma}$/W, $Zsb{gamma}$/Z and $Wsb{gamma}/Zsb{gamma}$, which, along with the previous CDF measurement(s) of the W/Z cross section ratio provide new insight on the Standard Model, and are sensitive to anomalous couplings of the W and Z bosons. Using the $Wsb{gamma}$ and $Zsb{gamma}$ absolute cross section measurements, the absence of an excess of hard photons accompanying W and Z boson production enables us to obtain direct limites on anomalous $WWsb{gamma}$, $ZZsb{gamma}$ and $Zsb{gammagamma}$ couplings. For saturation of unitarity, these experimental limits impose constraints on possible internal (composite) structure for the W and Z bosons with compositeness scale sensitivity up to $Lambdasb{W} sim$ 1 TeV and $Lambdasb{Z} sim$ 250-500 GeV, respectively. These compositeness scale limits probe the possible internal structure of the W to ${sim}

Inclusive Electroweak Measurements in the Muon Channel with Pp Collisions at [the Square Root Of] S

Inclusive Electroweak Measurements in the Muon Channel with Pp Collisions at [the Square Root Of] S
Author: Philip Coleman Harris
Publisher:
Total Pages: 243
Release: 2011
Genre:
ISBN:

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In this thesis, we perform the measurement of the production of W and Z bosons in proton-proton collisions at [the square root of]s = 7 TeV with the Large Hadron Collider (LHC). In the LHC, W and Z bosons are produced at a high rate, providing for large yields, which along with the clean signature of W boson decay into a muon and neutrino and the Z boson decay into two muons, allow for precision measurement of their production within the first year of operation. Deviation of these values from standard model predictions gives a clear indication of new physics interactions occurring at the LHC. We present the measurement of the inclusive W--> [mu] [epsilon] and Z --> [mu]+ [mu]- cross sections along with the W boson charge ratio (W+/W-) and the W/Z production ratio in the muon channel using the first data corresponding to 35.9 pb-1 of proton proton collisions at [the square root of]s = 7 TeV. Measured values of ... are in agreement with the most advanced NNLO predictions. These are currently the most precise Electroweak measurements at the LHC.