Measurement of Forward-Backward Asymmetry of Simulated and Reconstructed $Z' \to \mu^{+}\mu^{-}$ Events in CMS

This note describes a fitting technique for measuring the forward-backward asymmetry A_FB of Z' --> mu+ mu- events. We extract A_FB of fully simulated and reconstructed events by using an unbinned maximum likelihood fit based on a probability density function for six observables. We illustrate the potential for the measured on-peak A_FB to be used to distinguish among various couplings of a Z', such as those associated with Zssm, Zpsi, Zeta, Zchi, ZLRM, or ZALRM models. With 400 fb^-1 of integrated luminosity at CMS, one can distinguish between either a Zchi or ZALRM and one of the other four models with significance level alpha >= 3 sigma up to a Z' mass between 2.0 and 2.7 TeV. One can distinguish among the other four models with the same level of significance only up to Z' mass equal to 1 - 1.5 TeV, whereas ZALRM and Zchi are indistinguishable in the mass range of Z' mass >= 1 TeV.