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

TL;DR

This study conducted a high-statistics search for narrow baryon resonances decaying into specific Xi-pion channels, finding only known resonances and setting strict upper limits on potential exotic states near 1862 MeV.

Contribution

It provides the first high-statistics search for exotic baryons in these decay channels and establishes stringent upper limits on their production at 1862 MeV.

Findings

Only known Xi(1530) resonances observed

No evidence for exotic baryons near 1862 MeV

Set upper limits on production rates of potential new states

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 $\bar{\Xi^0}(1530)$. 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.