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

TL;DR

This paper investigates how a hypothetical new gauge boson Z' could induce lepton flavor violating decays of vector mesons and tau leptons, providing constraints on Z' models based on experimental limits.

Contribution

It calculates Z' contributions to LFV meson decays and tau decays, showing some models exceed experimental bounds, thus constraining Z' parameter space.

Findings

Z' models can significantly enhance LFV decay rates

The decay $ au o e extphi$ constrains Z' models more than $ au o 3e$

Some Z' models predict branching ratios above experimental limits

Abstract

Considering the constraints on the lepton flavor violating (LFV) couplings of the new gauge boson $Z'$ to ordinary leptons from the experimental upper limit for the LFV process $\ell\rightarrow 3\ell'$, we calculate the contributions of $Z'$ to the LFV decays $V\rightarrow\ell_{i}\ell_{j}$ with $V\in\{\phi,J/\Psi,\Psi(2S),\Upsilon^{(n)}\}$ and $\tau\to\mu(e)\phi$ in the context of several $Z'$ models. We find that all $Z'$ models considered in this paper can produce significant contributions to these decay processes and make the value of the branching ratio $Br(\tau\to e\phi)$ above its experimental upper limit. The experimental upper limit of $\tau\to e\phi$ can give more severe constraints on these $Z'$ models than those given by the rare decay process $\tau\to3e$.