Reduction of spectroscopic strength from nucleon knockout reactions*

The nuclear shell model pictures deeply bound nucleons as being in fully occupied states. At and above the Fermi surface, configuration mixing then leads to occupancies that gradually decrease to zero. This picture is modified in an important way by several correlation effects that are absent from, or are described only approximately by, effective-interaction theories, such as the shell model. This presentation will give a summary on the status of the reduction in spectroscopic strength as reported from Be- or C-induced one-nucleon knockout reactions.