New gauge boson Z' and lepton flavor violating decays and production of vector mesons

Abstract

Considering the constraints on the lepton flavor violating (LFV) couplings of the new gauge boson $Z^{\prime }$ to ordinary leptons from the experimental upper limit for the LFV process $\ell \to 3{\ell }^{\prime }$, we calculate the contributions of $Z^{\prime }$ to the LFV decays $V\to {\ell }_i{\ell }_j$ with $V\in \{\varphi ,J/\Psi ,\Psi (2S),{{\rm Y}}^{(n)}\}$ and $\tau \to \mu (e)\varphi$ in the context of several $Z^{\prime }$ models. We find that all $Z^{\prime }$ models considered in this paper can produce significant contributions to these decay processes and make the value of the branching ratio $Br(\tau \to e\varphi )$ above its experimental upper limit. The experimental upper limit of $\tau \to e\varphi$ can give more severe constraints on these $Z^{\prime }$ models than those given by the rare decay process $\tau \to 3e$.

Comments: Reference added, remove some typos; to be published in PRD