Observation of a baryon resonance with positive strangeness in K+ collisions with Xe nuclei

TL;DR

This paper reports the observation of a baryon resonance with positive strangeness in K+ collisions with xenon nuclei, indicating a potential exotic pentaquark state consistent with theoretical predictions.

Contribution

First experimental evidence of a baryon resonance with positive strangeness in K+Xe collisions aligning with anti-decuplet pentaquark models.

Findings

Resonance mass at 1539 MeV/c^2

Width less than 9 MeV/c^2

Statistical significance near 4.4 sigma

Abstract

The status of our investigation of low-energy $K^+$Xe collisions in the Xenon bubble chamber DIANA is reported. In the charge-exchange reaction $K^+Xe \to K^0 p Xe'$ the spectrum of $K^0 p$ effective mass shows a resonant enhancement with $M = 1539 \pm 2$ MeV/c$^2$ and $\Gamma \le 9 MeV/c$^2$. The statistical significance of the enhancement is near $4.4\sigma$. The mass and width of the observed resonance are consistent with expectations for the lightest member of the anti-decuplet of exotic pentaquark baryons, as predicted in the framework of the chiral soliton model.