Strong Interaction E ects in Stop Pair Production ate

We discuss perturbative and non{perturbative strong interaction eeects in the pair production of stop squarks (~ t 1) at e + e ? colliders. Events with an additional hard gluon allow to detect or exclude ~ t 1 ~ t 1 production even in scenarios with very small mass splitting between ~ t 1 and an invisible lightest supersymmetric particle (LSP). Such events can also help to establish that ~ t 1 transforms as a triplet under SU(3) C. We also carefully study non{perturbative ~ t 1 fragmentation, which is currently not well understood: not only is the ~ t 1 fragmentation function not known very well, but also there are ambiguities in the algorithm employed to model fragmentation. We present numerical results both for CERN LEP{183 and for a proposed future e + e ? collider operating at center{of{mass energy p s = 500 GeV.