The Search for Pentaquark Baryon with Hidden Strangeness

TL;DR

This paper reports evidence for a new baryon state, X(2000), observed in hyperon-kaon mass spectra, which may be a cryptoexotic pentaquark baryon with hidden strangeness, based on experimental data from the SPHINX Collaboration.

Contribution

It presents experimental evidence for a potential new pentaquark baryon with hidden strangeness, including analysis of its unusual decay features and supporting data.

Findings

Observation of X(2000) with narrow width

Unusual decay branching ratios involving strange particles

Supporting data confirming the existence of X(2000)

Abstract

Evidences for new baryon states with mass >1.8 GeV were obtained in the experiments of the SPHINX Collaboration in studying hyperon-kaon mass spectra in several proton diffractive reactions. The main result of these experiments is the observation of X(2000)->SIGMA K state with unusual dynamical features (narrow width, anomalously large branching ratios for the decay channels with strange particle emission). The possibility of the interpretation of this state as cryptoexotic pentaquark baryon with hidden strangeness is discussed. The additional data which are supported the real existence of X(2000) baryon are also presented.