Photoproduction of Pions in Carbon

Abstract

Positive and negative pions were produced by photons on a carbon target and observed at laboratory angles of 35\ifmmode^\circ\else\textdegree\fi{}, 73\ifmmode^\circ\else\textdegree\fi{}, and 121\ifmmode^\circ\else\textdegree\fi{}. At each angle the yield of mesons of constant energy was observed by a magnetic spectrometer as a function of peak bremsstrahlung energy. Seven values of the latter ranging from 205 to 335 Mev were used. Yields and $\frac{{\ensuremath{\pi}}^{\ensuremath{-}}}{{\ensuremath{\pi}}^{+}}$ ratios corrected for various systematic experimental errors are presented. By using a photon difference method the bremsstrahlung spectra were unfolded from the yield curves to give meson cross sections versus photon energy at fixed pion energies. These functions are compared with predicted yields which consider the internal momentum distribution of the target nucleons; the agreement is adequate.