Strength quenching in knockout reactions

Knockout reactions have been used extensively with radioactive beams to explore the single-particle structure of rare isotopes. Combined with an eikonal model that takes into account the inclusive nature of the experimental data, proton and neutron removal knockout cross sections have been used to extract spectroscopic factors in nuclei with a wide range of separation energies. When compared to independent particle models, these spectroscopic factors exhibit a clear trend from the most weakly to the most deeply bound nucleons. This quenching evolution may have its origin in correlations absent from the truncated-basis shell-model calculations or in the approximations used in the reaction dynamics. The quenching observed from knockout reactions on rare isotopes is not compatible with results from transfer or proton-induced quasi-elastic scattering. Experiments have so far demonstrated the robustness of the assumptions made in the eikonal model. Direct comparison with cross sections calculated using ab initio structure models that include correlations may pave the way in disentangling reaction mechanism from structure effects. In this talk the status of these studies will be presented, followed by recent progress and future plans to tackle these issues.