Meson-Nucleon Scattering and Asymptotic Conservation of Helicity

We have considered the validity and consistency of the hypothesis of asymptotic conservation of $s$-channel helicity, and the dynamical hypothesis that the $P^{\prime }$ Regge trajectory decouples from the $A$ amplitude in $\pi N$ and $\mathrm{KN}$ diffraction scattering. Sum rules which follow from these hypotheses are shown to be quite consistent with the experimental data.