Measurement of Angular Correlations in Drell–Yan Lepton Pairs to Probe Z/γ[superscript ⁎] Boson Transverse Momentum at √s = 7 TeV with the ATLAS Detector

[摘要] A measurement of angular correlations in Drell–Yan lepton pairs via the ϕ[* over η] observable is presented. This variable probes the same physics as the Z/γ[superscript ⁎] boson transverse momentum with a better experimental resolution. The Z/γ[superscript ⁎] → e[superscript +]e[superscript −] and Z/γ[superscript ⁎] → μ[superscript +]μ[superscript −] decays produced in proton–proton collisions at a centre-of-mass energy of √s = 7 TeV are used. The data were collected with the ATLAS detector at the LHC and correspond to an integrated luminosity of 4.6 fb[superscript −1]. Normalised differential cross sections as a function of ϕ[* over η] are measured separately for electron and muon decay channels. These channels are then combined for improved accuracy. The cross section is also measured double differentially as a function of ϕ[* over η] for three independent bins of the Z boson rapidity. The results are compared to QCD calculations and to predictions from different Monte Carlo event generators. The data are reasonably well described, in all measured Z boson rapidity regions, by resummed QCD predictions combined with fixed-order perturbative QCD calculations or by some Monte Carlo event generators. The measurement precision is typically better by one order of magnitude than present theoretical uncertainties.

[发布机构] Elsevier