Photoproduction evidence for and against hidden-strangeness states near 2 GeV

Abstract

Experimental evidence from coherent diffractive proton scattering has been reported for two narrow baryonic resonances which decay predominantly to strange particles. These states, with masses close to 2.0 GeV would, if confirmed, be candidates for hidden strangeness states with unusual internal structure. In this paper we examine the literature on strangeness photoproduction, to seek additional evidence for or against these states. We find that one state is not confirmed, while for the other state there is some mild supporting evidence favoring its existence. New experiments are called for, and the expected photoproduction lineshapes are calculated.