Non-factorizable corrections to W-pair production

In this paper we study the non-factorizable QED corrections to W-pair-mediated (charged-current) four-fermion production in electron-positron collisions. A brief account of the obtained analytical results is given. They turn out to be different from the ones published in the literature. Numerical results are presented, in particular the effects on the W line-shape. These effects are of the order of a per cent. The validity of the presented calculations starts a few widths above the W-pair threshold. Applying the same methods to ZZ- or ZH-mediated four-fermion production, the non-factorizable O(α) corrections to the Z or H line-shape vanish.