Search for Exotic Baryons in 800 GeV pp (rtarrow) pXiPiX

Abstract

We report the results of a high-statistics, sensitive search for narrow baryon resonances decaying to ${\Xi }^{-}{\pi }^{-}$, ${\Xi }^{-}{\pi }^{+}$, ${\bar{\Xi }}^{+}{\pi }^{-}$, and ${\bar{\Xi }}^{+}{\pi }^{+}$. The only resonances observed are the well known ${\Xi }^0(1530)$ and $\overline{{\Xi }^0}(1530)$. No evidence is found for a state near 1862 MeV, previously reported by NA49\cite{NA49}. At the 95% confidence level, we find the upper limit for the production of a Gaussian enhancement with $\sigma =7.6$ MeV in the ${\Xi }^{-}{\pi }^{-}$ effective mass spectrum to be 0.3% of the number of observed ${\Xi }^0(1530)\to {\Xi }^{-}{\pi }^{+}$. We find similarly restrictive upper limits for an enhancement at 1862 MeV in the ${\Xi }^{-}{\pi }^{+}$, ${\bar{\Xi }}^{+}{\pi }^{-}$, and ${\bar{\Xi }}^{+}{\pi }^{+}$ mass spectra.

Submitted to PRL