A measurement of angular correlations in Drell-Yan lepton pairs via the φη *observable is presented. This variable probes the same physics as the Z/γ*boson transverse momentum with a better experimental resolution. The Z/γ*→e+e-and Z/γ*→μ+μ-decays produced in proton-proton collisions at a centre-of-mass energy of s=7TeV are used. The data were collected with the ATLAS detector at the LHC and correspond to an integrated luminosity of 4.6 fb-1. Normalised differential cross sections as a function of φη *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 φη *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.
|Number of pages||20|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Publication status||Published - Mar 13 2013|
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics