Connection between Neutral Pion Decay and Proton Compton Scattering

Abstract

The inclusion of the single-pion intermediate state significantly improves the agreement between theory and experiment for proton Compton scattering. Excitation functions and angular distributions for various assumed values of the ${\ensuremath{\pi}}^{0}$ lifetime are presented. On this basis one may definitely exclude ${\ensuremath{\pi}}^{0}$ lifetimes >${10}^{\ensuremath{-}16}$ sec or 5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}19}$ sec.