Absolute spectroscopic factors from nuclear knockout reactions

Experimental cross sections at high energies for the C-12(O-16,N-15/O)X and C-12(C-12,B-11/C)X nucleon removal reactions are reduced by factors R-s=0.49-0.68 relative to calculations in the shell model and eikonal reaction theory. For protons, this is exactly what has been found in the (e,e'p) reaction. We suggest that nuclear knockout has potential for extending the measurement of precise orbital occupancies to neutron states and to a wide range of nuclei including rare radioactive species. The halo proton in radioactive B-8 turns out to have a stronger presence in the wave function with R-s=0.88(4).