Exact gauge invariant YFS exponentiated Monte Carlo for (un)stable W+W− production at and beyond LEP2 energies

Abstract We realize, by Monte Carlo event generator methods, the exact O (α) YFS exponentiated calculation of e + e − →W + W − (→f 1 f ′ 1 + f 2 f′ 2 ) at and beyond LEP2 energies, where the left-handed parts of f i and f ′ i are the respective upper and lower components of an SU 2 L doublet, i =1,2. Our calculation is gauge invariant from the standpoint of its radiative effects and the respective YFS Monte Carlo event generator YFSWW3, wherein both Standard Model and anomalous triple gauge boson couplings are allowed, generates n ( γ ) radiation both from the initial state and from the final W + W − . Sample Monte Carlo data are illustrated.