Measurement of Z boson production in the muon decay channel in lead-lead collisions at sqrt(s_NN)=2.76 TeV with the ATLAS detector

Abstract

The ATLAS detector at the LHC recorded data with an integrated luminosity of 142ub^-1 from lead-lead collisions at sqrt(s_NN)=2.76 TeV. A sample of 1223 Z bosons was reconstructed through the muon decay channel with high purity, enabling the most accurate measurement in heavy ion collisions conducted with Z bosons so far. The Z boson properties are studied as a function of transverse momentum and rapidity. The production rate of the Z boson is measured differentially with event centrality. Furthermore the azimuthal distribution of the Z boson emission with respect to the event plane is used to uncover potential modifications due to the collision geometry. Within statistical and systematic uncertainties, the per-event yield is proportional to the number of binary collisions estimated by the Glauber model, and the flow of the Z boson is found to be consistent with zero.