This talk will survey the current status of low energy scattering and electromagnetic production experiments of the pi-meson. These experiments test predictions based on spontaneous chiral symmetry breaking in QCD. The amplitude for the decay of the neutral pion into two gamma rays is dominated by the axial anomaly of QCD, modified by a small chiral correction which is proportional to the mass difference of the up and down quarks. These predictions have been tested by a new, precise lifetime measurement which will be discussed.
ANL Physics Division Colloquium Schedule