Lepton flavor violating decay Z-> l_i l_j in the 331 model

TL;DR

This paper investigates lepton flavor violating Z boson decays within the minimal 331 model, estimating branching ratios influenced by doubly charged bileptons and current experimental constraints, concluding these decays are unlikely to be observed soon.

Contribution

It provides the first estimate of LFV Z decay branching ratios in the 331 model considering current experimental bounds on bilepton couplings and masses.

Findings

Branching ratio for Z-> μτ below 10^{-10} for 500 GeV bilepton mass.

Bilepton contributions are too small for current experimental detection.

Bounds on bilepton mass derived from muon anomalous magnetic moment.

Abstract

We study the lepton flavor violating (LFV) decays Z-> l_i l_j (l_{i,j}=e,\mu,\tau) in the framework of the minimal 331 model. The main contributions arise at the one-loop level via a doubly charged bilepton with general LFV couplings. We obtain an estimate for the corresponding branching ratios by using the bounds on the LFV couplings of the doubly charged bilepton from the current experimental limits on the decays l_i-> l_j\gamma and l_i-> l_j l_k l_k. A bound on the bilepton mass is also obtained through the current limit on the anomalous magnetic moment of the muon. It is found that the bilepton contributions to LFV Z decays are not expected to be at the reach of experimental detection. In particular, the branching ratio for the Z-> \mu \tau decay is below the 10^{-10} level for a bilepton mass of the order of 500 GeV.