Rare decay of the top quark t→cll and single top quark production at the ILC

We perform a complete and detailed analysis of the flavor changing neutral current rare top quark decays t→cl+l- and t→cνiνi at one-loop level in the standard model, two Higgs doublet models (I and II), and in minimal supersymmetric standard model (MSSM). The branching ratios are very small in all models, O(10-14), except for the case of the unconstrained MSSM, where they can reach O(10-6) for e+e-, μ+μ-, and νiνi, and O(10-5) for τ+τ-. This branching ratio is comparable to the ones for t→cV, cH. We also study the production rates of single top and the forward-backward asymmetry in e+e-→tc and comment on the observability of such a signal at the International Linear Collider