Measurement of the WWγ and WWZ couplings at LEP200: the benefits of higher energy?

We performed a detailed analysis of the process e+e− → ℓνqq′ to determine its sensitivity to anomalous trilinear gauge boson couplings of the WWγ and WWZ vertices and how the sensitivity varies with energy and integrated luminosity. We included all tree level Feynman diagrams that contribute to this final state and used a maximum likelihood analysis of a five dimensional differential cross-section based on the W and W decay product angular distributions. For constant luminosity, increasing s from 175 GeV to 192 GeV (220 GeV) improves the measurement sensitivity by a factor of 1.5–2 (2–3) depending on the parameter measured. However, the lower luminosity expectd at higher s will reduce these improvements. In any case, the sensitivities for s=175 and L = 500 pb−1 of δg1z = ±0.22, δκz = ±0.20, δκγ = ±0.27, δL9l = ±5, and δL9r = −230+330 are likely to be at least an order of magnitude too big to see the effects of new physics.