Gauge Invariant YFS Exponentiation of (Un)stable $W^{+}{W}^{-}$ Production At and Beyond LEP2 Energies

Abstract

We present the theoretical basis and sample Monte Carlo data for the YFS exponentiated calculation of $e^{+}{e}^{-}\to W^{+}{W}^{-}\to f_1{\bar{f}}_1^{\prime }+{\bar{f}}_2{f}_2^{\prime }$ at and beyond LEP2 energies, where the left-handed parts of $f_i$ and $f_i^{\prime }$ are the respective upper and lower components of an $S{U}_{2L}$ doublet, $i=1,2$. The problem of gauge invariance of the radiation from the unstable charged spin~1 $W^{\pm }$ is solved in an entirely physical manner. Our formulas are illustrated in a proto-typical YFS Monte Carlo event generator YFSWW2, wherein both Standard Model and anomalous triple gauge boson couplings are allowed.

Comments: Latex replaces postscript, 17 pages