Strange-Particle Production by 1.95-BeV/cπ+in Hydrogen

Strange-particle production has been studied in 30 000 pictures taken in the BNL 20-in. hydrogen bubble chamber exposed to a 1.95-BeV/c separated ${\pi }^{+}$ beam. Cross sections are presented and the production of resonant states is discussed. The three-particle final states are dominated by ${Y_1}^{*}\mathrm{}\left(1385\right)\mathrm{}$, $K^{*}\mathrm{}\left(892\right)\mathrm{}$, and ${N_{\frac{1}{2}}}^{*}\mathrm{}\left(1688\right)\mathrm{}$. The angular distribution of ${\Sigma }^{+}$ in the ${\Sigma }^{+}{K}^{+}$ final state is presented, and comparison with a resonance-exchange model is discussed.