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 $π^{0}_{t}$ to the lepton flavor violating(LFV) processes $l_{i}\to l_{j}γ$ and $l_{i}\to l_{j}l_{k}l_{l}$. We find that the present experimental bound on $μ\to eγ$ 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 $Br(μ\to 3e)\simeq 2.87\times 10^{-14}$, $1.1\times 10^{-15}\leq Br(τ\to 3e)\simeq Br(τ\to 2eμ)\leq 4.4 \times 10^{-15} $, $3.1\times 10^{-15} \leq Br(τ\to 2μe)\simeq Br(τ\to 3μ)\leq 1.5 \times 10^{-14}$ in most of the parameter space.