Many-body effects in (p,pN) reactions within a unified approach

Abstract

We study knockout reactions with proton probes within a theoretical framework where ab initio Quantum Monte Carlo (QMC) wave functions are combined with the Faddeev/Alt-Grassberger-Sandhas few-body reaction formalism. QMC wave functions are used to describe 12C, yielding, for the first time, results consistent with the experimental root mean square (rms) point proton radii, (p,2p) total cross section data, as well as momentum distributions compatible with electron scattering data analysis. In our results for A≤12 and (N−Z)≤3 nuclei the ratios between the (i) theoretical cross sections evaluated using QMC and simple Shell Model structure inputs, and (ii) the corresponding ratios between the spectroscopic factors, summed over states below particle emission, are smaller than unity, pointing to the shortcomings of the simple Shell Model. This quenching is more significant for the knockout of the more correlated nucleon of the deficient species. These ratios can be represented reasonably well by a linear combination of the separation energy and the difference between the removed nucleon rms radius in the parent and residual nuclei, showing a mild dependence on these physical quantities. Keywords: Many-body ab initio structure, Correlations, Few-body reaction, (p,pN) reactions, Reduction factors