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

[摘要] A measurement of Wγ and Zγ 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[superscript −1]. The electron and muon decay channels of the W and Z are used. The total cross sections are measured for photon transverse energy E [γ over τ] > 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 M[subscript ℓℓ] > 50 GeV for the Zγ 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 WWγ, ZZγ, and Zγγ trilinear gauge couplings at √s = 7 TeV source are set.

[发布机构] Elsevier