Reconstructing the chargino system at $e^+e^-$ linear colliders

S.Y. Choi; A. Djouadi; M. Guchait; J. Kalinowski; H.S. Song; P.M. Zerwas

doi:doi:10.1007/s100520000365

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2024 Impact factor 4.8

Particles and Fields

Eur. Phys. J. C 14, 535-546
DOI 10.1007/s100520000365

Reconstructing the chargino system at e⁺e^- linear colliders

S.Y. Choi¹ - A. Djouadi² - M. Guchait³ - J. Kalinowski⁴ - H.S. Song⁵ - P.M. Zerwas³

¹ Korea Institute for Advanced Study, Seoul 130-012, Korea
² Phys. Math. et Théorique, Université Montpellier II, 34095 Montpellier, France
³ Deutsches Elektronen-Synchrotron DESY, 22603 Hamburg, Germany
⁴ Inst. Theor. Physics, Warsaw University, 00681 Warsaw, Poland
⁵ Center for Theor. Physics and Dep. of Physics, Seoul National University, Seoul 151-742, Korea

Received: 2 February 2000 / Published online: 17 March 2000 - © Springer-Verlag 2000

Abstract
In most supersymmetric theories charginos, $\tilde{\chi}^\pm_{1,2}$ , belong to the class of the lightest supersymmetric particles. The chargino system can be reconstructed completely in e⁺e^- collider experiments: $e^+e^-\rightarrow\tilde{\chi}_i^+ \tilde{\chi}_j^- \, \, [i,j=1,2]$ . By measuring the total cross sections and the asymmetries with polarized beams, the chargino masses and the gaugino-higgsino mixing angles of these states can be determined accurately. If only the lightest charginos $\tilde{\chi}_1^\pm$ are kinematically accessible in a first phase of the machine, transverse beam polarization or the measurement of chargino polarization in the final state is needed to determine the mixing angles. 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 $\mu$ , and $\tan\beta = v_2/v_1$ , 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. Sum rules of the cross sections can be exploited to investigate the closure of the two-chargino system.