Strong Interaction Effects in Stop Pair Production at $e^{+}{e}^{-}$ Colliders

Abstract

We discuss perturbative and non-perturbative strong interaction effects in the pair production of stop squarks (${\tilde{t}}_1$) at $e^{+}{e}^{-}$ colliders. Events with an additional hard gluon allow to detect or exclude stop pair production even in scenarios with very small mass splitting between ${\tilde{t}}_1$ and an invisible lightest supersymmetric particle (LSP). Such events can also help to establish that ${\tilde{t}}_1$ transforms as a triplet under $SU(3{)}_C$. We also carefully study non-perturbative ${\tilde{t}}_1$ fragmentation, which is currently not well understood: not only is the ${\tilde{t}}_1$ 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 $\sqrt{s}=500$ GeV.

Comments: 16 pages and 4 figures