Production of supersymmetric particles at high-energy colliders

The production and decay of supersymmetric particles is presented in this thesis. The search for light mixing top squarks and neutralinos/charginos will be a major task at the upgraded Tevatron and the LHC as well as at a future e"+e"- linear collider. The dependence of the hadro-production cross section for weakly and strongly interacting particles on the renormalization and factorization scales is found to be weak in next-to-leading order supersymmetric QCD. This yields an improvement of derived mass bounds or the measurement of the masses, respectively, of neutralinos/charginos and stops at the Tevatron and at the LHC. Moreover, the next-to-leading order corrections increase the predicted neutralino/chargino cross section by +20% to +40%, nearly independent of the mass of the particles. The consistent treatment as well as the phenomenological implications of scalar top mixing are presented. The corrections to strong and weak coupling induced decays of stops, gluinos, and heavy neutralinos [including mixing stop particles] are strongly dependent on the parameters chosen. The decay widths are defined in a renormalization scheme for the mixing angle, which maintains the symmetry between the two stop states to all orders. The correction to the stop production cross sections, depending on the fraction of incoming quarks and gluons, varies between -10% to +40% for an increasing fraction of incoming gluons. The dependence of the cross section on all parameters, except for the masses of the produced particles, is in contrast to the light-flavor squark case negligible. The calculation of the stop production cross section was applicable to the Tevatron search for particles which could be responsible for the HERA anomaly. (orig.)60 refs.Available from TIB Hannover: RR 8919(1998-024) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman