Forward-Backward Asymmetry of di-Lepton Pairs and the Weak-mixing Angle

We present a measurement of the forward-backward asymmetry (A$_{\rm FB}$) of opposite sign lepton pairs ($e^+e^-$ and $\mu^+\mu^-$) produced via an intermediate Z/$\gamma*$ in LHC proton-proton collisions at $\sqrt{s}$ = 7 TeV. We also present a measurement of the effective weak-mixing angle ($\theta_{\rm eff}$) via a multivariate likelihood fit of the rapidity, di-lepton invariant mass, and decay angle distributions. Our results are based on an integrated luminosity up to 40~pb$^{-1}$. We present A$_{\rm FB}$ as a function of mass in the range $40< {\rm M}_{\ell^{+}\ell^{-}}<600$~GeV range. From the dominant $u\bar{u}$ and $d\bar{d}\to Z/\gamma^*\to \mu^+\mu^-$ processes, we measure $\sin^2\theta_{\rm eff}=0.2287\pm 0.0077\pm 0.0036$. We find both the A$_{\rm FB}$ and the $\sin^2\theta_{\rm eff}$ measurements to be consistent with the Standard Model predictions within uncertainties.