Lepton flavor violating decays of vector mesons

TL;DR

This paper estimates the extremely suppressed rates of lepton flavor violating decays of vector mesons using an effective Lagrangian approach, setting stringent theoretical upper limits far below current experimental sensitivities.

Contribution

It provides model-independent upper bounds on lepton flavor violating meson decays based on existing experimental constraints, highlighting their near-impossibility of detection.

Findings

Derived upper limit for Br(φ → eμ) ≤ 1.3 × 10^{-21}

Established that detection of these decays is currently unfeasible

Provided a framework for constraining LFV processes without specific new physics models

Abstract

We estimate the rates of lepton flavor violating decays of the vector mesons $\rho, \omega, \phi \to e \mu$. The theoretical tools are based on an effective Lagrangian approach without referring to any specific realization of the physics beyond the standard model responsible for lepton flavor violation (\Lfv). The effective lepton-vector meson couplings are extracted from the existing experimental bounds on the nuclear $\mu^--e^-$ conversion. In particular, we derive an upper limit for the \Lfv branching ratio ${\rm Br}(\phi \to e \mu) \leq1.3 \times 10^{-21}$ which is much more stringent than the recent experimental result ${\rm Br}(\phi \to e \mu) < 2 \times 10^{-6}$ presented by the SND Collaboration. Very tiny limits on \Lfv decays of vector mesons derived in this letter make direct experimental observation of these processes unrealistic.