  The measurements of proton-proton elastic scattering for large momentum
transfer at energies in the range $\approx$ 20 to 60 GeV show a simple
behaviour of form $d \sigma/dt \approx {\rm const}~|t|^{-8}$, apparently with
no energy dependence. In the present work detailed analysis of the data shows a
decrease of the magnitude of the tail with the energy, still with preservation
of the power $|t|^{-8}$. The analysis allows the definition of a band for the
energy dependence with the form of a power of the strong coupling
$\alpha_S^{1.57}$. The rate of decrease describes very well the data at the
distant energy $\sqrt{s}$ = 13 TeV, with reduction of the cross section by a
factor 5.71. This result gives prediction for new experiments at high energies,
and opens important question for theoretical investigation.
