Quasifree Scattering of 160-Me V Protons from Nuclei

Using 160-Me V protons and a NaI total-energy scintillation counter we have measured the spectra of outgoing protons from 40 to 160 MeV at angles of 10-80 deg for a number of targets, ${\mathrm{Be}}^9$, ${\mathrm{C}}^{12}$, ${\mathrm{Ca}}^{40}$, ${\mathrm{Ni}}^{58}$, ${\mathrm{Sn}}^{120}$, and ${\mathrm{Bi}}^{209}$. The data have been interpreted by means of an impulse-approximation calculation. We have modified the usual analysis to calculate the scattering from nuclei, for which we assume that an extreme shell model is a valid representation. The differential cross section thus calculated can be expressed in terms of the momentum of the struck nucleon. We find that the shell-model description does not give enough high-momentum components to the nucleon wave functions. This is deduced because the experimental results necessitate high-momentum components to be able to produce high-energy large-angle outgoing protons.