Analysis of 9700 events, containing at least one observed neutral or charged decay, produced by $6-\frac{\mathrm{BeV}}{c}$ protons in the LRL 72-in. liquid-hydrogen bubble chamber has yielded 1746 examples of the reaction $\mathrm{proton}+\mathrm{proton}\to \mathrm{hyperon}+K\mathrm{meson}+\mathrm{nucleon}$. Production cross sections for these three-body reactions are as follows:

$\sigma \left(\Lambda K^{+}p\right)=54_{-5\mathrm{}}^{}{}_{}{}^{+3\mathrm{}}$μb, $\sigma \left({\Sigma }^0{K}^{+}p\right)=17_{-2\mathrm{}}^{}{}_{}{}^{+4\mathrm{}}$μb, $\sigma \left({\Sigma }^{+}{K}^{0}p\right)=26\mathrm{}\pm 4$μb, $\sigma \left({\Sigma }^{+}{K}^{+}n\right)=57\mathrm{}\pm 7$μb.

Strong $N^{*}$ production is observed in all channels. In particular, one or more $T=\frac{1}{2}$ resonant states with mass near 1700 $\frac{\mathrm{MeV}}{c^2}$, decaying into $\Lambda K^{+}$, and a $T=\frac{3}{2}$ resonance with mass 1920 $\frac{\mathrm{MeV}}{c^2}$, decaying into ${\Sigma }^{+}{K}^{+}$, are produced. In all cases the data are consistent with a production process dominated by a single-pion-exchange mechanism. No evidence is found for a dibaryon state in either the $\Lambda$-proton or $\Sigma$-nucleon system.

• Received 31 August 1967

DOI:https://doi.org/10.1103/PhysRev.165.1466