A Realistic Approach to the Standard Z Peak

The use of four gauge invariant form factors allows a dense notation of electroweak one loop effects in muon pair production frome+e−-annihilation. These form factors may be interpreted as finite renormalizations of the muon decay constant and of the weak mixing angle. Such a formulation is well adopted for use in Monte Carlo programs. The general formulae are applied to a realistic line shape scan of theZ boson resonance. For a precise determination of theZ boson's mass and width it is sufficient to take data in the small energy region within\(\sqrt s = M_z \pm \Gamma _z /2\). Finally, it is demonstrated that a simple model independent ansatz yields nearly equally good results.