Complete initial state QED corrections to off-shell gauge boson pair production in e+e− annihilation Original Research Article

We study Standard Model four-fermion production in e+e− annihilation at LEP2 energies and above using a semi-analytical approach. We derive the complete QED initial state corrections (ISR) to the reactions e+e− → (Z0Z0) → f1f1f2f2 and e+e− → (W+W− → f1u f1df2uf2d with f1 ≠ f2 and fi ≠ e−, →(W+W−). As compared to the well-known universal s-channel ISR, additional complexity arises due to non-universal, process-dependent ISR contributions from t and u-channel fermion exchanges. The formulae needed to perform numerical calculations are given together with samples of numerical results.