Nuclear interactions of 5.7 BeV protons in photographic emulsion

Abstract

Abstract Tracks produced by 5·7 Bev protons in nuclear emulsions have been followed till they interact with emulsion nuclei, and a mean free path of 35·6 × 2·4 cm has been obtained. About 24% of the shower tracks are found to be protons, all of which emerge at angles less than 20% with the direction of the primary. The mean multiplicity of pion production is found to be 2·6 ± 0·3, the coefficient of inelasticity 0·49 ± 0·07, and the transverse momentum of pions 220 ± 30 Rev/c. The angular distribution of the shower tracks has been analysed on the assumption that the pious are produced in a single collision system with a forward–backward symmetry in the centre of mass reference frame. The mass of the particle with which the incident proton forms such a collision, is shown to have an upper limit of 1·08 ± 0·15 proton mass units. Hence the meson production on an average may be considered as arising in a nucleon–nucleon collision even with a complex target nucleus. The angular distribution of the pions in the C-system is found to be isotropic, within the limits of experimental errors.