  Brand-new high-precision data for single-spin asymmetry $A_N(t)$ in small
angle elastic $pp$ scattering from the fixed target experiment HJET at BNL at
$E_{lab}=100$ and $255 \mbox{ GeV}$, as well as high energy STAR measurements
at $\sqrt{s}=200 \mbox{ GeV}$, for the first time allowed to determine the
spin-flip to non-flip ratio $r_5(t)$ in a wide energy range. We introduced an
essential modification in the Coulomb-nuclear interference (CNI) mechanism,
missed in previous analyses. It can be formulated either as a modification of
the Coulomb phase, which is much larger for the spin-flip compared with
non-flip amplitudes, or as absorptive corrections to the electromagnetic
interaction of hadrons. The Regge analysis singles out the Pomeron contribution
to the spin-flip amplitude, which steeply rises with energy. We found the
spin-flip to non-flip ratio of the Pomeron amplitudes to be nearly $-10\%$,
steeply rising with energy in accordance with theoretical expectations.
