Study of nuclear correlation effects via C12(p→,n→)N12(g.s.,1+) at 296 MeV

We report measurements of the cross section and a complete set of polarization observables for the Gamow-Teller C12(p→,n→)N12(g.s.,1+) reaction at a bombarding energy of 296 MeV. The data are compared with distorted wave impulse approximation calculations employing transition form factors normalized to reproduce the observed beta-decay ft value. The cross section is significantly under-predicted by the calculations at momentum transfers q≳0.5fm−1. The discrepancy is partly resolved by considering the non-locality of the nuclear mean field. However, the calculations still under-predict the cross section at large momentum transfers of q≃1.6fm−1. We also performed calculations employing random phase approximation response functions and found that the observed enhancement can be attributed in part to pionic correlations in nuclei.