Absolute spectroscopic factors from nuclear knockout reactions

Experimental cross sections at high energies for the ¹²C(¹⁶O,¹⁵N/O)X and ¹²C(¹²C,¹¹B/C)X nucleon removal reactions are reduced by factors Rₛ=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 ⁸B turns out to have a stronger presence in the wave function with Rₛ=0.88(4).