Dipole and quadrupole polarizabilities of the pion

Abstract

Data on pion polarizabilities obtained in different experiments are reviewed. The values of the dipole and quadrupole polarizabilities of the pi^0 and pi^{+-} mesons found are compared with predictions of dispersion sum rules (DSRs) and two-loop calculations in the framework of chiral perturbation theory (ChPT). Possible reasons of a difference between the predictions of DSRs and ChPT are discussed.

Comments: 3 pages, contribution to proceedings of "NSTAR 2007", 5-8 September, Bonn, Germany; typos corrected