Structure function formulation of $e^{+}{e}^{-}\to f\overline{f}$ around the $Z^0$ resonance in a realistic setup

A structure function approach to $e^{+}{e}^{-}$ annihilation into fermion pairs and to large-angle Bhabha scattering at energies reached at the CERN LEP and/or SLAC SLC is described. Higher-order QED corrections to cross sections and forward-backward asymmetries are computed according to a semianalytical procedure which accounts for realistic experimental cuts on the final state fermions. The effect of cuts on the $f\overline{f}$ acollinearity angle, energies or invariant mass, and angular acceptance of the outgoing fermions is investigated at the level of initial state radiation. The interplay between initial- and final-state QED corrections in the presence of experimental cuts is also discussed. In the case of Bhabha scattering the contribution of unresolved hard collinear photons to calorimetric measurement is analytically included as well. A general formula for QED effects in the presence of realistic cuts is proposed and analytically worked out in order to obtain fast and high-precision numerical predictions.