Measurement of the forward-backward asymmetry of $Z/\gamma^{*}$ bosons decaying into electron and muon pairs with the ATLAS detector at $\sqrt{s}=7$ TeV

This note presents a study by the ATLAS experiment of lepton pairs from $Z/\gamma^{*}$-boson decay. The results are based on the full set of data collected in 2011 in pp collisions at the LHC at $\sqrt{s}$ = 7 TeV, corresponding to an integrated luminosity of 4.8 fb$^{-1}$. The forward-backward asymmetry ($A_{FB}$) in the $Z$-boson rest-frame is measured and used to determine the effective weak mixing angle, $\sin^2{\theta_\mathrm{W}^{\mathrm{\,eff}}}$. The combination of the muon and electron channels yields a value of $\sin^2{\theta_\mathrm{W}^{\mathrm{\,eff}}}=0.2297 \pm 0.0004 \mathrm{(stat.)} \pm 0.0009 \mathrm{(syst.)}$.