Proton-tungsten reactions at 400 GeV

Abstract We report from an experiment where 400 GeV protons interact with tungsten nuclei in thin wires laminated into nuclear emulsion. The mean multiplicities of black, grey and shower track producing particles are found to be 11.5±0.4, 5.2±0.2 and 20.0±0.6, respectively. The correlations between different particle categories are studied and we find that the correlation between black and grey prongs is dependent on the target mass, while the correlation between the grey prongs and the shower particles are similar to the one found when lighter elements are used as targets. This provides evidence that the grey prong particles (recoiling protons) are a measure of the number of collisions inside the nucleus.