Dipole Polarizabilities of $\pi^{\pm}$-Mesons

TL;DR

This paper reviews experimental measurements of charged pion dipole polarizabilities, discusses discrepancies among data, highlights the impact of the $\sigma$-meson correction, and provides new fit results for the $\gamma\gamma o\pi ext o$ reaction.

Contribution

It introduces a correction involving the $\sigma$-meson to existing polarizability measurements and offers new fit results for the $\gamma\gamma o\pi o$ reaction.

Findings

The $\sigma$-meson significantly affects polarizability values.

Discrepancies among experimental data are analyzed.

New fit results for the $\gamma\gamma o\pi o$ reaction are presented.

Abstract

The main experimental works, where dipole polarizabilities of charged pions have been determined, are considered. Possible reasons for the differences between the experimental data are discussed. In particular, it is shown that the account of the $\sigma$-meson gives a significant correction to the value of the polarizability obtained in the latest experiment of the COMPASS collaboration. We present also new fit results for the $(\gamma\gamma\to\pi\pi)$ reaction.