Electroweak radiative corrections to e(+)e(-) -> WW -> 4 fermions in double-pole approximation - the RACOONWW approach

We calculate the complete O(alpha) electroweak radiative corrections to e()e(-) --> WW --> 4f in the electroweak Standard Model in the double-pole ap proximation. We give analytical results for the non-factorizable virtual co rrections and express the factorizable virtual corrections in terms of the known corrections to on-shell W-pair production and W decay. The calculatio n of the bremsstrahlung corrections, i.e., the processes e(+)e(-) --> 4f ga mma in lowest order, is based on the full matrix elements. The matching of soft and collinear singularities between virtual and real corrections is do ne alternatively in two different ways, namely by using a subtraction metho d and by applying phase-space slicing. The O(alpha) corrections as well as higher-order initial-state photon radiation are implemented in the Monte Ca rlo generator RACOONWW. Numerical results of this program are presented for the W-pair-production cross section, angular and W-invariant-mass distribu tions at LEP2. We also discuss the intrinsic theoretical uncertainty of our approach. (C) 2000 Elsevier Science B.V. All rights reserved.