Three-body calculations for (p ,p N ) reactions: Kinematically inclusive, semi-inclusive, and fully exclusive cross sections
Abstract
Background: Nucleon knockout reactions have been previously used to extract single particle information from nuclei. The analysis of nucleon knockout from a stable projectile in the collision with a proton target and the comparison with the experimental data is a key test for the reaction and structure models used to evaluate the reaction observables.
Purpose: We analyze p and n knockout from 12C, assuming that only the heavy fragment or core C (taken as inert), the knockout particle N , and the proton target p participate in the collision process with the aim of (i) getting insight to the dominant kinematic conditions of the emitted particles; (ii) clarifying the dynamics of the reaction; (iii) exploring the isospin dependence (here p and n knockout) of the calculated reaction cross sections. Method: We solve three-body Faddeev/Alt-Grassberger-Sandhas (Faddeev/AGS) equations for transition operators and calculate kinematically fully exclusive, semi-inclusive, and inclusive cross sections. Results: We show that (i) the dominant final-state kinematic conditions are consistent with the assumption of quasifree scattering reaction mechanism; (ii) the distortions due to higher order multiple scattering terms depend on the final-state kinematics, and the N -C and p -C final state interaction provide significant effects in the calculated observables; (iii) the twofold energy-polar angle and polar angle-polar angle cross sections exhibit distinct p - and n -knockout behaviors. Finally we also show that the Faddeev/AGS formalism is able to a certain extent to reproduce the available experimental data for the p knockout. Conclusions: Kinematically fully exclusive measurements of p and n knockout are needed to rigorously assess the role of the distortion, as it cannot be taken into account as an overall reduction factor. This is a prerequisite for a reliable understanding of the structure of the projectile and the reaction mechanism. In addition, realistic interactions inferred from ab initio structure models are needed for analyzing experimental data.- Publication:
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Physical Review C
- Pub Date:
- May 2019
- DOI:
- 10.1103/PhysRevC.99.054622
- Bibcode:
- 2019PhRvC..99e4622C