Constraining a CP-violating WWV coupling from the W+W− threshold cross section at LEP2

The most general form of the WWZ and WWγ interaction contains a CP-violating term which has the same threshold behaviour as the Standard Model e+e− → W+W− cross section. We calculate the cross section as a function of the corresponding anomalous xoupling, and estimate the bounds which can be obtained from a measurement of the threshold cross section at LEP2. We show how the effect of the coupling is most pronounced in the angular distributions of the final-state fermions.