The general properties of the scattering amplitude and the experimental data on the total and
the differential cross sections of $\pi^\pm p$ forward scattering yield \begin{gather}
\int^\infty_{30\mathrm{\,GeV}}\ln\biggl(\frac{d\sigma_+(E,0)}{dt}\bigg/\frac{d\sigma_-(E,0)}{dt}\biggr)\frac{dE}E=-0.112\pm0.025,
\
\int^\infty_{60\mathrm{\,GeV}}\frac{\sigma_+(E)-\sigma_-(E)}E\,dE=-0.103\pm0.016.
\end{gather}