Electroweak radiative corrections to resonant charged gauge boson production

The electroweak $O\left(\alpha \right)$ contribution to the resonant single $W$ production in a general four-fermion process is discussed with particular emphasis on a gauge-invariant decomposition into a QED-like and weak part. The cross section in the vicinity of the resonance can be represented in terms of a convolution of a “hard” Breit-Wigner cross section, comprising the ${(m}_t{,M}_H)$-dependent weak one-loop corrections, with a universal radiator function. The numerical impact of the various contributions on the $W$ line shape are discussed, together with the concepts of $s$-dependent and constant width approaches. Analytic formulas for the $W$ decay width are also provided including the one-loop electroweak and QCD corrections.