SUSY-induced top quark FCNC processes at linear colliders

Abstract

In the Minimal Supersymmetric Model (MSSM) the hitherto unconstrained flavor mixing between top-squark and charm-squark will induce the flavor-changing neutral-current (FCNC) interaction between top quark and charm quark, which then lead to various processes at the next generation linear collider (NLC), i.e., the top-charm associated productions via e + e −, e − γ and γγ collisions as well as the top quark rare decays t→ cV ( V= g, γ or Z). All these processes involve the same part of the parameter space of the MSSM. Through a comparative analysis for all these processes at the NLC, we found that the best channel to probe such SUSY-induced top quark FCNC is the top-charm associated production in γγ collision, which occurs at a much higher rate than e + e − or e − γ collision and may reach the detectable level for some part of the parameter space.