How large is the missing strength in (e,e'p) reactions

This paper reports on the spectroscopic information deduced from quasi-free proton knockout that can be related to the overlap integral between the ground state of the target nucleus and the final state of the residual nucleus. Restricting the analysis to one single peak of the cross section produces a spectroscopic factor which describes how the residual nucleus can be considered as a pure hole in the target nucleus. Integrating the nuclear response over the entire fragmentation of the hole strength leads to the occupation probability of the involved orbit. The observed occupation numbers in (e,e'p) reactions in general are lower than one would expect from pure shell model and/or from correlated basis function theory