Chargino Pair Production at $e^+e^-$ Colliders with Polarized Beams

Abstract

The chargino $\tildeχ^\pm_{1,2}$ system can be reconstructed completely in $e^+e^-$ collisions. By measuring the total cross sections and the asymmetries with polarized beams in $e^+e^-\to\tildeχ_i^+ \tildeχ_j^- [i,j=1,2]$, the chargino masses and the gaugino-higgsino mixing angles of these states can be determined very accurately. If only the lightest charginos $\tildeχ_1^\pm$ 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 $M_2$, the modulus and the cosine of the CP-violating phase of the higgsino mass parameter $μ$, and $\tanβ= v_2/v_1$, the ratio of the vacuum expectation values of the two neutral Higgs doublet fields. [The remaining two-fold ambiguity of the phase can be resolved by measuring the normal polarization of the charginos.]