Photoproduction of Positive Pions from Carbon Nuclei

Abstract

Positive pions with energies ranging from 30 MeV to 150 MeV were produced on a carbon target by the bremsstrahlung beam from the 750-MeV electron-synchrotron and detected by means of a π-µ decay counter telescope at an angle of 90° in the laboratory. The counts were corrected for the electronic efficiency of the pion counting system and for the loss of pions in the detection system by decay in flight, nuclear absorption, nuclear scattering and multiple Coulomb scattering. Absolute cross sections of the pion production are given as a function of the peak bremsstrahlung energies extending from 180 MeV to 550 MeV. Applying the photon difference method to the cross section per equivalent quantum, the differential cross sections, (\(d^{2}\sigma/d\varOmega dT_\pi\)) and (\(d\sigma/d\varOmega\)), are obtained, and compared with theoretical values, which are calculated on the bases of the impulse and closure approximation, the nuclear momentum distribution of a Gaussian type of the average kinetic energy of 19 Me...