  The normal and pairing self-energies are the microscopic quantities which
reflect and characterize the underlying interaction in superconductors. The
momentum and frequency dependence of the self-energies, therefore, provides the
experimental criteria which can single out the long sought-after pairing
interaction among many proposed ideas. This line of research to pin down the
pairing interaction for the cuprate superconductors has been carried out with
some success by analyzing the momentum distribution curves of laser
angle-resolved photo-emission spectroscopy (ARPES) data. Some progress and
results are presented and compared with theoretical calculations based on
leading proposals. Comments are made on the proposed scenarios from the
comparisons.
