Strange-Particle Production by 3-BeV/c π− Mesons in Hydrogen

Over 600 strange-particle events were identified on the basis of both kinematical fitting and bubble-density information. The center-of-mass angular distributions generally show the familiar backward tendency for the baryons and forward tendency for the $K$ mesons. Invariant mass distributions show the production of several resonant states including the ${{Y}_{1}}^{*}(1385 \mathrm{MeV})$, ${K}^{*}(885 \mathrm{MeV})$, and ${{Y}_{0}}^{*}(1405 \mathrm{MeV})$. The two-body reactions ${\ensuremath{\pi}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}{K}^{*}+{{Y}_{1}}^{*}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}{K}^{*}+{{Y}_{0}}^{*}$ are also reported and studied. The two-, three-, and four-particle reactions are discussed and an attempt is made to put limits on the $S{U}_{3}$ multiplet of the ${f}^{0}$ from the number of ${{K}_{1}}^{0}{{K}_{1}}^{0}$ events with a mass near the ${f}^{0}$. The cross sections are calculated and the total strange-particle cross section at this energy is estimated to be $\ensuremath{\sigma}=(1.68\ifmmode\pm\else\textpm\fi{}0.20)$ mb.