We consider high-energy quasifree single- and two-proton knockout reactions induced by electrons and protons and address the question of what target-nucleus densities can be effectively probed after correcting for nuclear attenuation (initial- and final-state interactions). Our calculations refer to ejected proton kinetic energies of 1.5 GeV, the reactions $(e,e^{\text{'}}p)$, $(\gamma ,\mathit{pp})$, and $(p,2p)$, and a carbon target. It is shown that each of the three reactions is characterized by a distinctive sensitivity to the density of the target nucleus. The bulk of the $(\gamma ,\mathit{pp})$ strength stems from the high-density regions in the deep nuclear interior. Despite the strong attenuation, sizable densities can be probed by $(p,2p)$ reactions provided that the energy resolution allows one to pick nucleons from $s$ orbits. The effective mean densities that can be probed in high-energy $(e,e^{\text{'}}p)$ reactions is of the order of 30%–50% of the nuclear saturation density.

• Received 8 April 2009

DOI:https://doi.org/10.1103/PhysRevC.80.011602