Complete electroweak O(α) corrections to charged-current e+e−→4 fermion processes

The complete electroweak O(α) corrections are calculated for the charged-current four-fermion production processes e+e−→νττ+μ−ν¯μ, ud¯μ−ν¯μ, and ud¯sc¯. The calculation is performed using complex gauge-boson masses, supplemented by complex couplings to restore gauge invariance. The evaluation of the occurring one-loop tensor integrals, which include 5- and 6-point functions, requires new techniques. Explicit numerical results are presented for total cross sections in the energy range from the W-pair-production threshold region up to a scattering energy of 2 TeV. A comparison with the predictions based on the “double-pole approximation” (DPA) provided by the generator RacoonWW reveals corrections beyond DPA of ≲0.5% in the energy range 170-300 GeV, in agreement with previous estimates for the intrinsic DPA uncertainty. The difference to the DPA increases to 1-2% for s∼1-2TeV. At threshold, where the DPA becomes unreliable, the full O(α) calculation corrects an improved Born approximation (IBA) by about 1.6%, also consistent with an error estimate of the IBA.