One-loop contributions of charginos and neutralinos to W+ W- production   in e+ e- collisions
  We study one-loop effects of charginos and neutralinos on the helicity amplitudes for the process $e^+e^-\to W^+W^-$ in the MSSM. The calculation is tested by using two methods. First, the sum rules among form factors which result from BRS invariance. Second, the decoupling property in the large mass limit is used to test the overall normalization of the amplitudes. The one-loop contribution to the helicity amplitudes is shown as a function of $\mu$ Higgs parameter and $\sqrt{s}$. We also study the effects of the CP-violating phase. 
Kaoru Hagiwara, Shinya Kanemura, Yoshiaki Umeda