== Gamma/Z interference in e+e- -> mu+ mu- ==
* Calculate analytically the cross section for %$e^+ e^- \to \mu^+ \mu^-$% as function of the CMS energy, including
both exchange of a photon and a Z boson. Neglect masses of the external fermions. Compare your result with
Software.MadGraph.
* The Forward-Backward asymmetry is
%$A_{FB}(\theta)=\frac{ d\sigma (\theta) - d\sigma(\pi-\theta)}{ d\sigma (\theta) + d\sigma(\pi-\theta)}$%.
Plot it as a function of the CMS energy.
-- Main.FabioMaltoni - 30 Aug 2007