From analysis of $V^0$ events observed in an exposure of the National Accelerator Laboratory 30-in. bubble chamber to $303-\frac{\mathrm{GeV}}{c}$ protons, we obtain these results: (1) $〈n_{\pi 0}〉$ rises approximately linearly with $n$-, implying strong coupling of neutral and charged pions, while $〈n_{K_S^{}{}_{}{}^0}^{}{}_{}{}^{}〉$ is less coupled to $n$; (2) $\gamma$, $K_S^{}{}_{}{}^0$, and ${\Lambda }^0$ production cross sections are approaching a scaling limit by 303 $\frac{\mathrm{GeV}}{c}$; (3) within the limited statistics, $\frac{d\sigma }{\mathrm{dy}}$ is flat in the central region for $K_S^{}{}_{}{}^0$ and low-multiplicity $\gamma$ events.

• Received 9 April 1973

DOI:https://doi.org/10.1103/PhysRevLett.30.1151