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−→χ̃i+χ̃j− [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 χ̃1± 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 tanβ=v2/v1, 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.