FINAL-STATE RADIATION AND LINE-SHAPE DISTORTION IN RESONANCE PAIR PRODUCTION

In this letter it is shown how final-state QED corrections to the prod uction of a pair of resonances can distort the line shape of such a re sonance in a sizeable way. This effect depends on the definition of th e line shape and can reach up to 30%, depending on the final state. Th e mechanism is first displayed for a particular case of ZZ production, for which an exact and approximate treatment can be given. The approx imate method is then applied to W-pair production. In addition some si mple rules of thumb an given for accurately estimating the characteris tic distortion effects, like the mass shift and peak reduction. (C) 19 98 Elsevier Science B.V. All rights reserved.