Cross-Section Asymmetries Around the $Z$ Peak

A simple model-independent formula for cross-section asymmetries $A$ in fermion-pair production is derived, which may be used for the analysis of LEP~1 data, $A = \sum_n A_n (s - M_Z^2)^n$. The coefficient $A_0$ depends on the $Z$ boson exchange, $A_1$ additionally on the $\gamma Z$ interference, while the higher-order contributions are practically redundant. QED corrections are taken into account, and relations to other approaches are indicated.