Chargino pair production at e⁺ e^- colliders with polarized beams

By measuring the total cross sections and the asymmetries with polarized beams in e⁺e^-→ X(i)/⁺X(j)/^- [i,j = 1,2], the chargino masses and the gaugino-higgsino mixing angles of these states can be determined very accurately. If only the lightest charginos X₁(±) are kinematically accessible, transverse beam polarization is needed to determine the mixing angles unambiguously. From these observables the fundamental SUSY parameters can be derived: the SU(2) gaugino mass M₂, the modulus and the cosine of the CP-violating phase of the higgsino mass parameter μ, and tan β = ν₂/ν₁, the ratio of the vacuum expectation values of the two neutral Higgs doublet fields. Sum rules of the cross sections can be exploited to investigate the closure of the two-chargino system. (C) 2000 Elsevier Science B.V.