Pion polarizabilities: Theory vs Experiment

Abstract

The values of charged pion polarizabilities obtained in the framework of chiral perturbation theory at the level of two-loop accuracy are compared with the experimental result recently reported by COMPASS Collaboration. It is found that the calculated value for the dipole polarizabilities $(\alpha -\beta {)}_{{\pi }^{\pm }}=(5.7\pm 1.0)\times 10^{-4}{\mathrm{fm}}^3$ fits quite well the experimental result $(\alpha -\beta {)}_{{\pi }^{\pm }}=(4.0\pm 1.2_{\mathrm{stat}}\pm 1.4_{\mathrm{syst}})\times 10^{-4}{\mathrm{fm}}^3$.

Comments: 12 pages, 7 figures. Talk given at the 9th joint International HADRON STRUCTURE'15 Conference, GRAND HOTEL BELLEVUE, Horny Smokovec, Slovak Republic, 29 June - 3 July, 2015