Non-universal gauge bosons $Z^{\prime }$ and lepton flavor-violation tau decays

Abstract

There are many models beyond the standard model predicting the existence of non-universal gauge bosons $Z^{\prime }$, which can give rise to very rich phenomena. We calculate the contributions of the non-universal gauge bosons $Z^{\prime }$, predicted by topcolor-assisted technicolor (TC2) models and flavor-universal TC2 models, to the lepton flavor-violation tau decays $\tau \to l_i\gamma$ and $\tau \to l_i{l}_j{l}_k$. We find that the branching ratio $B_r(\tau ⟶l_i{l}_j{l}_k)$ is larger than that of the process $\tau ⟶l_i\gamma$ in all of the parameter space. Over a sizable region of the parameter space, we have $B_r(\tau ⟶l_i{l}_j{l}_k)\sim 10^{-8}$, which may be detected in the future experiments.

Comments: Final version to appear in Phys. Lett. B. References added and typos corrected