Dipole polarizabilities of light pseudoscalar mesons within the Domain Model of QCD vacuum

TL;DR

This paper calculates the dipole polarizabilities of light pseudoscalar mesons using a QCD vacuum domain model, showing reasonable agreement with experimental and theoretical data, and highlighting the role of scalar mesons.

Contribution

It introduces a mean field approach within the domain model of QCD vacuum to compute meson polarizabilities, including the effects of scalar mesons and their propagators.

Findings

Polarizabilities agree with COMPASS data and Chiral Perturbation Theory.

Scalar meson contributions are significant but not dominant.

Scalar meson propagators lack poles at real momenta.

Abstract

Dipole polarizabilities of light pseudoscalar mesons are calculated in the framework of the mean field approach to QCD vacuum and bosonization based on the statistical ensemble of almost everywhere homogeneous Abelian (anti-)self-dual gluon fields -- the domain model of QCD vacuum. In this approach, one derives a nonlocal effective action of meson fields which describes two-point correlation functions and all possible strong, weak and electromagnetic interactions of meson fields including their excited states. Specifically, the role of intermediate scalar meson fields in formation of the polarizabilities is addressed. Within the domain model, the propagators of scalar meson fields composed of light quark-anti-quark pairs have no poles at real momenta. It turns out that for charged pions and kaons, the contribution of intermediate scalar fields to polarizability is substantial, but not the largest one. The calculated polarizabilities are in reasonable agreement with COMPASS experimental data and results of Chiral Perturbation Theory.