We determine the accuracy of various approximations to the O(alpha) corrections for on-shell W-pair production. While an approximation based on the universal corrections arising from initial-state radiation, from the running of alpha, and from corrections proportional to m_t^2 fails in the Linear-Collider energy range, a high-energy approximation improved by the exact universal corrections is sufficiently good above about 500GeV. These results indicate that in Monte Carlo event generators for off-shell W-pair production the incorporation of the universal corrections is not sufficient and more corrections should be included.
@article{arxiv.hep-ph/9706388,
title = {Approximations for W-Pair Production at Linear-Collider Energies},
author = {A. Denner and S. Dittmaier},
journal= {arXiv preprint arXiv:hep-ph/9706388},
year = {2007}
}