The study of a flavor-changing neutral toppion production process $e^+e^-\to t\bar{c}\Pi_t^0$

We have studied a flavor-changing toppion production process $e^{+}e^{-}\to t\bar{c}\Pi^{0}_{t}$ in the topcolor-assisted technicolor(TC2) model. The studies show that, with high centre of mass energy in TESLA collider, the production cross section of $e^{+}e^{-}\to t\bar{c}\Pi^{0}_{t}$ is at the order of magnitude 0.1 fb in most parameter regions of TC2 model and a few tens events of toppion can be produced each year. The resonance effect can enhance the cross section to a few fb when toppion mass is small. With clean background, the toppion events can possibly be detected at TESLA collider. On the other hand, we find that there exists a narrow peak near $m_t-m_c$ in the toppion-charm invariant mass distribution which could be clearly detected. Therefore, such a toppion production process $e^{+}e^{-}\to t\bar{c}\Pi^{0}_{t}$ provides a unique chance to detect toppion events and test the TC2 model.