π0Production Cross Section for 430-Mev Protons on H and Be

Abstract

The differential cross section for the production of photons in the forward direction by the reaction (430-Mev $p+H\ensuremath{\rightarrow}p+p+{\ensuremath{\pi}}^{0}$; ${\ensuremath{\pi}}^{0}\ensuremath{\rightarrow}2\ensuremath{\gamma}$) is measured as 0.20\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}27}$ ${\mathrm{cm}}^{2}$/sterad. The ratio of total to differential gamma cross section does not depend strongly on the symmetry of pion emission. Using an average calculated ratio, we find the pion-production cross section from hydrogen to be 0.45\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}27}$ ${\mathrm{cm}}^{2}$.The differential gamma-production cross section in the forward direction on Be is measured to be 4.35\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}27}$ ${\mathrm{cm}}^{2}$/sterad. We assume that in analogy with the case of H the ratio of total to differential photon cross section will not depend on symmetry of pion emission. Using the ratio calculated for isotropic emission we find ${{\ensuremath{\sigma}}_{\ensuremath{\pi}}}^{0}=8.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}27}$ ${\mathrm{cm}}^{2}$.