Reaction K−p→Ξ−K0π+ at 2.18 GeVc

Abstract

From 730 $K^{-}p\to {\Xi }^{-}{K}^0{\pi }^{+}$ events at 2.18 $\frac{\mathrm{GeV}}{c}$ a sample of $324{\Xi }^{*0\mathrm{}}\mathrm{}\left(1531\right)\mathrm{}$ decaying to ${\Xi }^{-}{\pi }^{+}$ has been analyzed. This sample yields a mass $M=1531.3\mathrm{}\pm 0.6$ MeV, corrected for systematic shifts. A width of $\Gamma =8.4\mathrm{}\pm 1.4$ MeV is obtained; the mass resolution was unfolded taking account of the non-Gaussian nature of the resolution function. In addition, the ${\Xi }^{*0\mathrm{}}\mathrm{}\left(1635\right)\mathrm{}$ reported by the Brandeis-Maryland-Syracuse-Tufts Collaboration is not detected. An upper limit of less than 2 μb (90% confidence level) is obtained for the cross section. The energy dependence of the $\Xi K$ and ${\Xi }^{*}\mathrm{}\left(1531\right)K$ cross sections would suggest a substantial cross section (∼7.5 ± 3 μb) for ${\Xi }^{*}\mathrm{}\left(1635\right)K$ at 2.18 $\frac{\mathrm{GeV}}{c}$. Thus either this state does not exist, or the energy dependence of its production cross section is different from that observed for the $\Xi K$ and ${\Xi }^{*}\mathrm{}\left(1531\right)K$ reactions.