Beyond the known baryon resonances

Abstract

eta photoproduction data on the proton up to E=2 GeV are interpreted within a chiral constituent quark formalism, which embodies all known three and four star resonances. This study confirms the need for a new S11 resonance, with M=1.780 GeV and Gamma=280 MeV, already introduced in investigating lower energy data.

Comments: 5 pages, 1 figure; invited talk given at Nstar2002 Workshop on the Physics of Excited Nucleons, Pittsburgh, Pennsylvania, Oct. 9-12, 2002