Chiral Symmetry and Low-Energy Pion-Photon Reactions

This talks reviews tests of Chiral Perturbation Theory via low-energy pion-photon reactions. In the COMPASS experiment at CERN, the Primakoff scattering of high-energy pions on nuclear targets is used to extract cross section for $\pi^-\gamma$ reactions. Depending on the hadronic final state, one is able to extract the electric and magnetic pion-polarizabilities from pion-Compton scattering or test the QCD chiral anomaly in $\pi^-\gamma \to \pi^-\pi^0$.  The dynamics involved in neutral and charged pion-pair production is that of pion-pion interaction in an electromagnetic environment. The QED radiative corrections to these processes will are by studied. A further topic will be the estimation of radiative corrections to the proton and neutron magnetic moments.