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

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.