Measurement of angular correlations in Drell-Yan lepton pairs to probe Z/gamma* boson transverse momentum at sqrt(s)=7 TeV with the ATLAS detector

A measurement of angular correlations in Drell-Yan lepton pairs via the @f_@h^@? observable is presented. This variable probes the same physics as the Z/@c^@? boson transverse momentum with a better experimental resolution. The Z/@c^@?->e^+e^- and Z/@c^@?->@m^+@m^- 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^-^1. Normalised differential cross sections as a function of @f_@h^@? 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 @f_@h^@? 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.