Radiative corrections to pair production of unstable particles: results for e^+e^- --> 4 fermions

Abstract

Radiative corrections to processes that involve the production and subsequent decay of unstable particles are complex due to various theoretical and practical problems. The so-called double-pole approximation offers a way out of these problems. This method is applied to the reaction $e^{+}{e}^{-}\to W^{+}{W}^{-}\to 4$fermions, which allows us to address all the key issues of dealing with unstable particles, like gauge invariance, interactions between different stages of the reaction, and overlapping resonances. Within the double-pole approximation the complete $\text{OO}(\alpha )$ electroweak corrections are evaluated for this off-shell $W$-pair production process. Examples of the effect of these corrections on a number of distributions are presented. These comprise mass and angular distributions as well as the photon-energy spectrum.

Comments: 59 pages, LaTeX2e (uses axodraw.sty), 16 figures