Neutral top-pion and top-charm production in high energy e+e− collisions

We calculate the contributions of the neutral top-pion, predicted by topcolor-assisted technicolor (TC2) theory, to top-charm production via the processes γγ→t̄c and e+e−→γγ→t̄c at the high energy linear e+e− collider (LC) experiments. The cross section is of order 10−2 pb in most of the parameter space of TC2 theory, which may be detected at the LC experiments. So the process e+e−→t̄c can be used to detect the signature of TC2 theory.