Searches for Gauge Mediated SUSY Breaking at LEP.pdf

2 0 SEARCHES FOR GAUGE MEDIATED SUSY BREAKING AT LEP 0 2 K. KLEIN y a University of Heidelberg, Physikalisches Institut, M Philosophenweg 12, 69120 Heidelberg, Germany 9 Searches for neutralinos and sleptons with arbitrary lifetimes, as predicted in the framework 2 of the Gauge Mediated Supersymmetry Breaking (GMSB) model, have been performed by the four LEP collaborations. No evidence for these particles has been found in the data recorded √ 1 v at center–of–mass energies up to s = 209 GeV. Therefore constraints on the production 6 cross–sections and particle masses as well as interpretations in the framework of the GMSB 9 model are presented. 0 5 0 1 Introduction 2 0 1 / In supersymmetry (SUSY) for every Standard Model (SM) particle a supersymmetric “part- x e ner”, differing in spin by half a unit, is predicted. If SUSY were an exact symmetry, the super- - symmetric particles would be degenerate in mass with their Standard Model partners. However, p e since no SUSY particles have been observed so far, it can be deduced that the SUSY partners h must be much heavier than (most of) the Standard Model particles, and therefore SUSY must : v be a broken symmetry. Several mechanisms for SUSY breaking have been considered. One i X approach is that SUSY is broken in a “hidden” sector, which couples to the visible sector con- r taining the SM and SUSY particles via gravitational interactions (gravity media