Study ofK−pInteractions at 4.1 and 5.5GeVc: Final States with Two Charged Particles and a VisibleΛ

Abstract

The results described in this paper were obtained from an analysis of bubble-chamber pictures of ${K}^{\ensuremath{-}}p$ interactions at incident momenta of 4.1 and 5.5 $\frac{\mathrm{GeV}}{c}$. This paper reports the results on quasi-two-body final states, which are observed to be predominantly peripheral. In the final states $\ensuremath{\Lambda}\ensuremath{\rho}$, $\ensuremath{\Lambda}\ensuremath{\omega}$, $\ensuremath{\Lambda}\ensuremath{\varphi}$, and ${{Y}_{1}}^{*+}(1385){\ensuremath{\pi}}^{\ensuremath{-}}$, the exchange mechanisms were investigated in terms of the density-matrix formalism. In general, vector-meson exchange appeared to be dominant, and in particular the decay distributions of the ${{Y}_{1}}^{*+}(1385){\ensuremath{\pi}}^{\ensuremath{-}}$ final state were in good agreement with the predictions of the Stodolsky-Sakurai model. Several reactions show small backward peaks expected from baryon exchange. The prediction of the independent quark model and other symmetry schemes that the forward cross sections for $\ensuremath{\Lambda}{\ensuremath{\rho}}^{0}$ and $\ensuremath{\Lambda}\ensuremath{\omega}$ production should be equal is well satisfied by the present data. We also report measurements of the properties of various resonant states. We find a mass and width for the ${{Y}_{1}}^{*}(1695)$ of $M=1700\ifmmode\pm\else\textpm\fi{}20$ MeV, $\ensuremath{\Gamma}=130\ifmmode\pm\else\textpm\fi{}25$ MeV. The dominant decay mode is $\ensuremath{\Lambda}{\ensuremath{\pi}}^{+}$, but limits are placed on other possible channels.