A simple approximation of the one-loop corrected cross section for e(+)e(-)->W+W- at LEP 2

Using the SU(2) gauge coupling, g(W)+/- (M-W+/-(2)), at the high-energy scale of MW+/-, defined by the (theoretical value of the) leptonic W-width, rather than using the low-energy value, defined via the Fermi coupling, G(mu), in the Born approximation, and supplementing with Coulomb corrections and initial state radiation, errors with respect to the exact one-loop results for the differential cross section of e(+)e(-) --> W+W- are below 1% at LEP 2 energies at all W+W- production angles. A similar procedure is suggested to incorporate leading bosonic loop effects into four-fermion production in the fermion-loop scheme. The resulting accuracy below 1% is sufficient for LEP 2 experiments. (C) 1997 Published by Elsevier Science B.V.