Coincident proton emission induced by 200 MeV protons on 197Au

Coincident cross sections were measured for the reaction 197Au(p,p'p'') at an incident energy of 200 MeV. The protons emitted from the continuum were detected at primary laboratory angles of -40 degree, -50 degree, and -60 degree, for secondary angles ranging between 20 degree and 150 degree. The theoretical model which was used to interpret the coincident spectra describes the reaction mechanism in terms of a quasifree nucleon-nucleon interaction between the projectile and a bound target nucleon, folded with a probability for emission of the quasifree knocked-on nucleon after inelastic rescattering off the residual target nucleus. The validity of the distorted-wave impulse approximation which describes the initial quasifree interaction was confirmed by measuring the quasifree knockout of valence-orbital protons from 197Au. The measured coincident continuum cross sections were then compared with model calculations for primary proton energy cuts around 90, 70, and 40 MeV. The reasonable agreement found between the calculated and measured cross sections indicates that the signature of quasifree scattering persists in the continuum emission from a nucleus as heavy as 197Au, and is not obscured by multiple scattering efects