We study the inclusive reactions ${\pi }^{-}+p\to {\pi }^{-}$ +anything at 8, 18.5, and 24.8 $\frac{\mathrm{GeV}}{c}$ and ${\pi }^{+}+p\to {\pi }^{-}$ +anything at 18.5 $\frac{\mathrm{GeV}}{c}$. Distributions of the particle density $\frac{\omega \left(\frac{d\sigma }{d{p}_{\parallel }}\right)}{{\left({\sigma }_T\right)}_{\infty }}$ at $p_{\parallel }\lesssim 1 \frac{\mathrm{GeV}}{c}$ for the "inclusive" ${\pi }^{-}$ indicate an approach to limiting behavior for ${\pi }^{+}p$ at current accelerator energies. Invariant cross sections for ${\pi }^{-}p$ decrease significantly in magnitude as the incident energy increases. The decrease is consistent with an energy dependence similar to the form $A+{Bs}^{\frac{-1}{2}}$ suggested by Regge phenomenology, approaching the ${\pi }^{+}p$ limiting distribution as a limit.

• Received 21 July 1971

DOI:https://doi.org/10.1103/PhysRevLett.27.1164