Measurement of the $Z$ Boson production with the ATLAS Experiment at the LHC

The inclusive and single differential in Z boson rapidity bins cross sections for the pp -> Z/gamma -> e+e− process are measured with the ATLAS detector at the LHC. The data are taken in 2010 at a center-of-mass energy of sqrt(s) = 7 TeV and correspond to an integrated luminosity of 36.2 pb−1. Several types of systematic uncertainties, including pileup effects, efficiency corrections and differences in Monte-Carlo generators are considered. The dominant uncertainty comes from the electron identification efficiency correction. All results are in agreement with the muon channel analysis and with theoretical predictions. The calibration of the ATLAS electromagnetic calorimeter using Z ! e+e− events is performed for all sub-detectors up to |eta| = 4.9 in bins of electron eta. Several tests of the calibration method as well as studies of the systematic uncertainties are presented. Total uncertainties of the calibration factors do not exceed 2% for the region where the cross section is measured. The electron identification and isolation efficiency measurements are studied using a tag-and-probe method. The results are in agreement with the other ATLAS measurement. The dominant systematic uncertainty, which comes from the background subtraction, is estimated using several fit methods.