Chargino Production and Decay in Photon-Photon-Collisions

We discuss the pair production of charginos in collisions of polarized photons $\gamma\gamma \to \tilde{\chi}_i^+ \tilde{\chi}_i^-$, ($i=1,2$) and the subsequent leptonic decay of the lighter chargino $\tilde{\chi}_1^+ \to \tilde{\chi}_1^0 e^+ \nu_e$ including the complete spin correlations. Analytical formulae are given for the polarization and the spin-spin correlations of the charginos. Since the production is a pure QED process the decay dynamics can be studied separately. For high energy photons from Compton backscattering of polarized laser pulses off polarized electron beams numerical results are presented for the cross section, the angular distribution and the forward-backward asymmetry of the decay positron. Finally we study the dependence on the gaugino mass parameter $M_1$ and on the sneutrino mass for a gaugino-like MSSM scenario.Comment: 22 pages, 15 figures, version to be published in Eur. Phys. J.

Determination of the Gaugino Mass Parameter M_1 in Different Linear Collider Modes

We study the different linear collider modes with regard to the determination of the gaugino mass parameter M_1. In a specific mSUGRA inspired scenario we compare four processes with polarized beams: (a) e+ e- --> neutralino_1 neutralino_2 --> neutralino_1 neutralino_1 e+ e-, (b) e- gamma --> neutralino_1 selectron_{L/R} --> neutralino_1 neutralino_1 e-, (c) gamma gamma --> chargino_1^+ chargino_1^- --> neutralino_1 neutralino_1 e+ e- neutrino_e anti-neutrino_e, (d) e- e- --> selectron_{L/R} selectron_{L/R} --> neutralino_1 neutralino_1 e- e-.Comment: 5 pages, 8 figures, LaTex, Talk given at the 5th International Linear Collider Workshop (LCWS 2000), Fermilab, Batavia, Illinois, Oct. 24-28, 200

Selectron pair production at e"-e"- colliders and e"+e"- colliders with polarized beams

We investigate selectron pair production and decay in e"-e"- scattering and e"+e"- annihilation with polarized beams taking into account neutralino mixing as well as ISR and beamstrahlung corrections. One of the main advantages of having both modes at disposal is their complementarity concerning the threshold behaviour of selectron pair production. In e"-e"- the cross sections at threshold for e_Re_R and e_Le_L rise proportional to the momentum of the selectron and in e"+e"- that for e_Re_L. Measurements at threshold with polarized beams can be used to determine the selectron masses m_e__L__/__R precisely. Moreover we discuss how polarized electron and positron beams can be used to establish directly the weak quantum numbers of the selectrons. We also use selectron pair production to determine the gaugino mass parameter M_1. This is of particular interest for scenarios with non-universal gaugino masses at a high scale resulting in vertical stroke M_1 vertical stroke >> vertical stroke M_2 vertical stroke at the electroweak scale. Moreover, we consider also the case of a non-vanishing selectron mixing and demonstrate that it leads to a significant change in the phenomenology of selectrons. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(01-173) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

TESLA : The superconducting electron positron linear collider with an integrated X-ray laser laboratory. - Technical design report. Pt. 6 : Appendices. Chapter 1 : The photon collider at TESLA

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TESLA : The superconducting electron positron linear collider with an integrated X-ray laser laboratory. - Technical design report. Pt. 6 : Appendices. Chapter 1 : The photon collider at TESLA

Etoil