Z′ and anomalous gauge coupling effects at LEP2 and their separation

In the case of the process e+e−→μ+μ−, we study the sensitivity to either Z′ or anomalous gauge coupling effects of two new observables, σ+ and σ−, conveniently defined for such kind of analysis. We discuss general properties of the deviations of these observables from the Standard Model predictions, and derive the model-independent bounds on the relevant parameters allowed by present and foreseeable LEP2 data. We also discuss the possibility of separating the two kinds of effect.