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Measurement of Wγ and Zγ production in pp collisions at √s = 7 TeV
Journal article   Open access   Peer reviewed

Measurement of Wγ and Zγ production in pp collisions at √s = 7 TeV

Francisco Javier Cuevas Maestro, Javier Fernández Menéndez, Santiago Folgueras Gómez, Isidro González Caballero, Lara Lloret Iglesias, Jesús Manuel Vizán García and CMS Collaboration
Physics letters. B, Vol.701(5), pp.535-555
01/01/2011
DOI: 10.1016/j.physletb.2011.06.034
url
https://doi.org/10.1016/j.physletb.2011.06.034View
Published (Version of record) Open Access

Abstract

A measurement of W-gamma and Z-gamma production in proton-proton collisions at sqrt(s) = 7 TeV, based on a data sample recorded by the CMS experiment at the LHC, and corresponding to an integrated luminosity of 36 inverse picobarns, is presented. 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. 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. A measurement of W γ and Z γ production in proton–proton collisions at 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 pb−1 . The electron and muon decay channels of the W and Z are used. The total cross sections are measured for photon transverse energy ETγ>10 GeV and spatial separation from charged leptons in the plane of pseudorapidity and azimuthal angle ΔR(ℓ,γ)>0.7 , and with an additional dilepton invariant mass requirement of Mℓℓ>50 GeV for the Z γ process. The following cross section times branching fraction values are found: σ(pp→Wγ+X)×B(W→ℓν)=56.3±5.0(stat.)±5.0(syst.)±2.3(lumi.) pb and σ(pp→Zγ+X)×B(Z→ℓℓ)=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 γ , ZZ γ , and Z γγ trilinear gauge couplings at s=7 TeV are set.
Astrophysics High Energy Physics Particle Physics Physics 114 Physical sciences E(+)E Electroweak Experiment Física gamma gamma Z High Energy Astrophysical Phenomena Nuclear Nuclear Experiment Phenomenology Physique des particules élémentaires pp 7 TeV

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