Proton-Proton Collisions at 4.2 Bev

Abstract

Interactions between 4.15-Bev protons and the free hydrogen nuclei in nuclear emulsion are examined. The total elastic cross section from 27 events was determined to be 11.0\ifmmode\pm\else\textpm\fi{}2.6 mb. On the basis of 113 interactions the total inelastic cross section was found to be 28.1\ifmmode\pm\else\textpm\fi{}3.1 mb. The partial cross sections corresponding to inelastic collisions having two, four, six, and eight secondary particles were found to be respectively 16.3\ifmmode\pm\else\textpm\fi{}2.4, 11.5\ifmmode\pm\else\textpm\fi{}1.8, 0.2\ifmmode\pm\else\textpm\fi{}0.1, and 0.1\ifmmode\pm\else\textpm\fi{}0.1 mb. While the total inelastic cross section varies slowly with energy, the partial inelastic cross sections were found to be strongly energy dependent. The observed angular distribution of elastically scattered protons in the center-of-mass system was sharply peaked in the forward and backward directions, in fair agreement with calculations based on a simple optical model applicable for energies between 2 and 10 Bev. Particles produced in inelastic collisions were identified as pions or protons by measurements of energy loss and multiple scattering. For those particles identified, center-of-mass system distributions of energy, angle, and transverse momentum are presented.