Measurement of W gamma and Z gamma production in pp collisions at root s=7 TeV

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 cro...

Full description

Bibliographic Details
Main Authors: Chatrchyan, S, Khachatryan, V, Sirunyan, A, Tumasyan, A, Adam, W, Bergauer, T, Dragicevic, M, Eroe, J, Fabjan, C, Friedl, M, Fruehwirth, R, Ghete, V, Hammer, J, Haensel, S, Hoch, M, Hoermann, N, Hrubec, J, Jeitler, M, Kasieczka, G, Kiesenhofer, W, Krammer, M, Liko, D, Mikulec, I, Pernicka, M, Rohringer, H
Format: Journal article
Language:English
Published: 2011
Description
Summary: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. © 2011 CERN.