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

The results described in this paper were obtained from an analysis of bubble-chamber pictures of $K^{-}p$ 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 $\Lambda \rho$, $\Lambda \omega$, $\Lambda \phi$, and ${Y_1}^{*+}\mathrm{}\left(1385\right)\mathrm{}{\pi }^{-}$, 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 ${Y_1}^{*+}\mathrm{}\left(1385\right)\mathrm{}{\pi }^{-}$ 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 $\Lambda {\rho }^0$ and $\Lambda \omega$ 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 ${Y_1}^{*}\mathrm{}\left(1695\right)\mathrm{}$ of $M=1700\mathrm{}\pm 20$ MeV, $\Gamma =130\mathrm{}\pm 25$ MeV. The dominant decay mode is $\Lambda {\pi }^{+}$, but limits are placed on other possible channels.