Rescattering effects for the 12C(p, 2 p)11B reaction at 400 MeV/u

Background: Single-particle occupancies for a wide range of magic and near-magic nuclei are significantly below the values predicted by independent-particle shell-model calculations. Purpose: We aim in this paper to address the question: To what extent does the extracted structure information have uncertainties due to approximations involved in the reaction formalism and assumed dynamic model? Method: The proton knockout reaction C-12( p, 2p)B-11 at 400 MeV/u incident energy is analyzed using the few-body Faddeev-Alt-Grassberger-Sandhas reaction framework. A two-body model is used for C-12 which involves an inert B-11(3/2(-))core and a valence proton. The contributions of higher order terms beyond the single scattering approximation are studied, in particular the ones corresponding to the rescattering between C-12 constituents. Results: Total cross section and core transverse momentum distribution are calculated. We have found that rescattering terms between the composite nucleus constituents contribute dominantly to the absorptive distortion. Conclusions: The accurate treatment of these rescattering terms in the reaction formalism is crucial if one aims to extract reliable structure information from the data. We have also found that work needs to be performed in the reaction theory in order to incorporate a complete structure description of the projectile nucleus and to bridge the proton knockout results with those obtained from electron scattering.