SUSY Loop Contributions to the $W$-Pair Production in $e^+e^-$   Collisions
  We discuss one-loop contributions of supersymmetry (SUSY) particles to the process $e^+e^- \to W^+W^-$ in the minimal supersymmetric standard model. The calculation is tested by using the sum rule among the form factors, which is based on the BRS invariance. The overall normalization factor of the amplitudes is tested by using the decoupling property of the SUSY particles in the large mass limit. The correction due to the one-loop effect of the sfermions can be of a few times $\pm 0.1$ % level, whereas that of the charginos and neutralinos can be order 1%. We also study the CP-violating effects in the chargino and neutralino sector. 
Kaoru Hagiwara, Shinya Kanemura, Yoshiaki Umeda