Probing the weak boson sector in e⁺e^-→W⁺W^-

A detailed analysis of W pair production in e⁺e^- annihilation at LEP-II energies is presented by using helicity amplitudes for the process e⁺e^-→W⁺W^- with arbitrary WWγ and WWZ couplings. Expressing the complete angular distribution of W decay products in terms of these helicity amplitudes, we perform a systematic search for the most sensitive angular distributions or correlations for anomalous couplings. As a result precise tests of the gauge-theory cancellations between different diagrams are suggested. Angular distributions sensitive to W⁺W^- rescattering effects and/or CP-violating vector boson couplings are studied as well. Complete helicity amplitudes for the process e⁺e^- → W⁺W^- → (q₁q₂g)(q₃q₄g) with arbitrary quark masses and finite W width are presented in a form convenient for their direct numerical evaluation. Amplitudes for the processes e⁺e^- → ZZ and Zγ are also included.