Study of the asymmetry of the cross section for production of cumulative protons in the reaction. gamma. A. -->. pX

The asymmetry in the cross section for the cumulative production of protons in the reaction ..gamma..A..-->..pX has been studied for several nuclei in the photon energy range 0.7--2.0 GeV. Quasimonochromatic photons were used. The asymmetry was determined from the difference in the yields with photons polarized perpendicular and parallel to the reaction plane. The asymmetry is found to be nearly independent of A, being nearly zero for carbon and somewhat larger for lead at the highest energy. (AIP)