Observation of a narrow structure in p(gamma,K_s)X via interference with phi-meson production

TL;DR

This paper reports the observation of a narrow resonance structure at 1.54 GeV in a photon-proton reaction, likely caused by interference effects involving strange baryon resonances and phi-meson production, with high statistical significance.

Contribution

It presents the first evidence of a narrow structure in the p(gamma,K_s)X reaction, suggesting interference effects with phi-meson production as a possible explanation.

Findings

Narrow peak at ~1.54 GeV with 6 MeV width observed.

Statistical significance of 5.3 sigma for the resonance.

Interference between baryon resonance and phi-meson production proposed.

Abstract

We report observation of a narrow peak structure at ~1.54 GeV with a Gaussian width sigma=6 MeV in the missing of K_s in the reaction gamma+p = pK_sK_L. The observed structure may be due to the interference between a strange (or anti-strange) baryon resonance in the pK_L system and the phi(K_sK_L) photoproduction leading to the same final state. The statistical significance of the observed excess of events estimated as the log likelihood ratio of the resonant signal+background hypothesis and the phi-production based background only hypothesis corresponds to 5.3 sigma.