Two-nucleon correlations and the structure of the nucleon spectral function at high values of momentum and removal energy

The basic two-nucleon configurations which generate the structure of the nucleon spectral function at high values of momenta and removal energies are analyzed. A model spectral function expressed through a convolution integral of the momentum distributions describing the relative and center-of-mass motion of a correlated pair is suggested and shown to satisfactorily reproduce the spectral function of the three-body system and nuclear matter calculated in terms of realistic nucleon-nucleon interactions in a wide range of nucleon momenta and removal energies.