Measurement of the Forward-backward in $Z/\gamma^* \rightarrow \ell^+\ell^-$ Events in CMS at $\sqrt{s}=7$ TeV

We present the initial steps in the measurement of the forward-backward asymmetry ($A_{\rm FB}$) for $\mu^+\mu^-$ pairs produced via an intermediate $Z/\gamma^*$ at $\sqrt{s} = 7$ TeV in the CMS experiment. Our results are based on an integrated luminosity of 198 nb$^{-1}$. The uncorrected forward-backward asymmetry is measured to be -0.50$\pm$0.40 in the mass range 40-70 GeV, and 0.14$\pm$0.11 in 70-110 GeV. The measured values are consistent with POWHEG + PYTHIA + full CMS simulation predictions of -0.03 and 0.01 in these two mass bins.