Compton Scattering on the Charged Pion and the Process \gamma\gamma \to \pi^0 \pi^0

Abstract

The Compton scattering on a charged pion and the process \gamma\gamma \to \pi^0\pi^0 are studied using the dispersion relations. Unknown parameters of the S-wave \pi\pi interaction, represented as a board Breit-Wignar resonance, and a sum and a difference of the \pi^0 meson polarizabilities are found from a fit to the experimental data for the process \gamma+\gamma \to \pi^0+\pi^0. This fit gives \alpha+\beta=0.98\pm 0.03 and \alpha-\beta=-1.6\pm 2.2. The found parameters of the S-wave \pi\pi interaction are used for the calculation of the cross section of the Compton scattering on \pi^{\pm} meson. The analysis of the obtained results shows that the experimental data for the elastic \gamma\pi scattering in the energy region up to 1 GeV together with the data for the process \gamma+\gamma \to \pi^0+\pi^0 could be used both for a determination of the pion polarizability values with quite high accuracy and for study of the S-wave \pi\pi interaction.