Proton knockout from 16O at 504 MeV and limitations of the DWIA

Abstract

Analyzing powers have been calculated for the (p, 2p) reaction on 16O at 504 MeV incident energy using a finite-ranged, relativistic DWIA formalism that includes both dynamical and kinematical recoil effects. A relativistic, Love-Franey parametrization is employed for the NN t-matrix, and distortions are incorporated by means of relativistic, energy-dependent global optical potentials. The results are compared with the data for knockout from the 1 S 1 2 , 1 P 1 2 , and 1 P 3 2 bound states. The calculated analyzing powers for P-state knockout agree fairly well with the data. For knockout from the 1 S 1 2 state, however, the DWIA results and the data are in significant disagreement. Further investigation has revealed a relationship between this disagreement and the spin-orbit parts of the phase-equivalent Schrödinger distortion potentials. Specifically, when the spin-orbit parts of the distortion potentials are omitted, the DWIA analyzing powers move closer to the data, particularly in their energy dependence. In so far as the presence and strength of the data, particularly in their energy dependence. In so far as the presence and strength of the spin-orbit potential is well established by other considerations, this is not a solution to the disagreement, but it may provide a clue for future work.