First application of the dispersive optical model to (p,2p) reaction analysis within the distorted-wave impulse approximation framework

Background: Both (e,e′p) and (p,2p) reactions have been performed to study the proton single-particle character of nuclear states with its related spectroscopic factor. Recently, the dispersive optical model (DOM) was applied to the (e,e′p) analysis revealing that the traditional treatment of the single-particle overlap function, distorted waves, and nonlocality must be further improved to achieve quantitative nuclear spectroscopy. Purpose: We apply the DOM wave functions to the traditional (p,2p) analysis and investigate the consistency of the DOM spectroscopic factor that describes the (e,e′p) cross section with the result of the (p,2p) analysis. Additionally, we make a comparison with a phenomenological single-particle wave function and optical potential. Uncertainty arising from a choice of p-p interaction is also investigated. Method: We implement the DOM wave functions to the nonrelativistic distorted-wave impulse approximation (DWIA) framework for (p,2p) reactions. Results: DOM + DWIA analysis on Ca40(p,2p)K39 data generates a proton 0d3/2 spectroscopic factor of 0.560, which is meaningfully smaller than the DOM value of 0.71 shown to be consistent with the (e,e′p) analysis. Uncertainties arising from choices of single-particle wave function, optical potential, and p-p interaction do not explain this inconsistency. Conclusions: The inconsistency in the spectroscopic factor suggests there is urgent need for improving the description of p-p scattering in a nucleus and the resulting in-medium interaction with corresponding implications for the analysis of this reaction in inverse kinematics.