Leading particle distributions in 200-gev/c P + A interactions

Distributions of the leading positive particle have been measured in collisions of a 200 GeV/c proton beam with hydrogen, Mg, Ag and Au targets using the FNAL Hybrid Spectrometer. Estimates of the rapidity loss of the projectile have been obtained as a function of the target mass, the multiplicity of negative particles and the number of recoil protons. We obtained a lower limit of the rapidity loss of 2.0±0.2 for central p+Au collisions. The impact parameter dependence of the momenta of the first few leading particles has also been investigated with important implications to estimates of energy densities obtained in central collisions