The neutral top-pion and the lepton flavor violating $Z$ decays $Z\to   l_{i}l_{j}$
  Taking into account the constraints of the present experimental limit of the process $\mu\to e\gamma$ on the free parameters of topcolor-assisted technicolor(TC2) models, we calculate the contributions of the neutral top-pion to the lepton flavor violating(LFV) $Z$ decays $Z\to l_{i}l_{j}$. Our results show that the value of the branching ratio $Br(Z\to \tau l)$ is larger than that of $Br(Z\to \mu e)$ in all of the parameter space and there is $Br(Z\to \tau\mu)\approx Br(Z\to \tau e)\simeq 2\times 10^{-14} $, which is far from the reach of present or future experiments. 
Chongxing Yue, Wei Wang, Feng Zhang