Properties of Soft Radiation Near and $W^{+}{W}^{-}$ Threshold

Abstract

We discuss the characteristic interference features of soft radiation in the threshold production of heavy unstable particles: soft gluon radiation in $\text{ee}\to$ and soft photon radiation in $\text{ee}\to \text{ww}$. We show that the heavy particle decay width controls the interference between the emission off the final state particles. As a result, the radiation pattern may provide a way of measuring the decay width of the heavy particles.

Comments: LaTeX, 33 pages + 10 figures not included but gladly provided by orr@ucdhep.ucdavis.edu; DTP/92/88, UCD-92-29, LU-TP-92-33