Evidence for a narrow structure at W~1.68 GeV in eta photoproduction on the neutron

Abstract

New results on quasi-free $\hat{I}\cdot$ photoproduction on the neutron and proton bound in a deuteron target are presented. The ${\hat{I}}^{3}n\to \hat{I}\cdot n$ quasi-free cross section reveals a bump-like structure which is not seen in the cross section on the proton. This structure may signal the existence of a relatively narrow ($M\sim 1.68$ GeV, $\hat{I}“\le 30$ MeV) baryon state.

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