Towards an effective field theory for vector mesons

TL;DR

This paper develops an effective field theory Lagrangian for light pseudoscalar and vector mesons, providing a systematic framework to analyze vector meson interactions and their electromagnetic form factors, including successes and failures of vector-meson dominance.

Contribution

It introduces a new effective Lagrangian inspired by EFT ideas that captures both VMD successes and deviations in meson electromagnetic form factors.

Findings

Reproduces pion form factors consistent with VMD

Accounts for deviations in omega transition form factor

Provides a systematic EFT approach for vector mesons

Abstract

The assumption that vector mesons dominate the interactions of hadrons with electromagnetism (vector-meson dominance - VMD) provides an important phenomenological concept. On the other hand, a clear microscopic derivation is still missing and there are cases where VMD drastically fails, e.g. for the omega transition form factor. In principle, effective field theories with their systematic expansion and power counting could provide a tool to assess the validity of VMD and more generally to describe the interactions of vector mesons at low energies. Though the systematic development is still in an infant stage we present here a Lagrangian for light pseudoscalar and vector mesons which is inspired by ideas from effective field theories. The Lagrangian is used to calculate electromagnetic meson form factors. It turns out that one can reproduce both the successes of VMD concerning the pion form factors and the deviations from VMD concerning the omega transition form factor.