Neutral top-pion and lepton flavor violating processes

Abstract

In the context of topcolor-assisted techicolor(TC2) models, we study the contributions of the neutral top-pion ${\pi }_t^0$ to the lepton flavor violating(LFV) processes $l_i\to l_j\gamma$ and $l_i\to l_j{l}_k{l}_l$. We find that the present experimental bound on $\mu \to e\gamma$ gives severe constraints on the free parameters of $TC2$ models. Taking into account these constraints, we consider the processes $l_i\to l_j{l}_k{l}_l$ generated by top-pion exchange at the tree-level and the one loop level, and obtain $Br(\mu \to 3e)\simeq 2.87\times 10^{-14}$, $1.1\times 10^{-15}\le Br(\tau \to 3e)\simeq Br(\tau \to 2e\mu )\le 4.4\times 10^{-15}$, $3.1\times 10^{-15}\le Br(\tau \to 2\mu e)\simeq Br(\tau \to 3\mu )\le 1.5\times 10^{-14}$ in most of the parameter space.

latex files,16 pages, 6 figures. Submitted to Phys. Rev. D