2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/211911New results on quasi-free $η$ photoproduction on the neutron and proton bound in a deuteron target are presented. The $γn \to ηn$ 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, $Γ\leq 30$ MeV) baryon state.Replaced with published versionHigh Energy Physics - Experimenttext