  The well-known Migdal-Luttinger theorem states that the jump of the
single-nucleon momentum distribution at the Fermi surface is equal to the
inverse of the nucleon effective E-mass. Recent experiments studying
short-range correlations (SRC) in nuclei using electron-nucleus scatterings at
the Jefferson National Laboratory (JLAB) together with model calculations
constrained significantly the Migdal-Luttinger jump at saturation density of
nuclear matter. We show that the corresponding nucleon effective E-mass is
consequently constrained to $M_0^{\ast,\rm{E}}/M\approx2.22\pm0.35$ in
symmetric nuclear matter (SNM) and the E-mass of neutrons is smaller than that
of protons in neutron-rich matter. Moreover, the average depletion of the
nucleon Fermi sea increases (decreases) approximately linearly with the isospin
asymmetry $\delta$ according to $\kappa_{\rm{p}/\rm{n}}\approx 0.21\pm0.06 \pm
(0.19\pm0.08)\delta$ for protons (neutrons). These results will help improve
our knowledge about the space-time non-locality of the single-nucleon potential
in neutron-rich nucleonic matter useful in both nuclear physics and
astrophysics.
