Evidence for a narrow N(1685) resonance in eta photoproduction off the nucleon

Abstract

Revised analysis of Sigma beam asymmetry for eta photoproduction off the free proton from GRAAL is presented. New analysis reveals a narrow structure near W ~1.685 GeV. We describe this structure by the contribution of a narrow resonance with quantum numbers P_{11}, or P_{13}, or D_{13}. Being considered together with the recent observations of a bump-like structure at W~1.68 GeV in the quasi-free eta photoproduction off the neutron, this result provides an evidence for a narrow (Gamma < 25 MeV) N*(1685) resonance. Properties of this possible new nucleon state, namely the mass, the narrow width, and the much stronger photocoupling to the neutron, are similar to those predicted for the non-strange member of anti-decouplet of exotic baryons.

arXiv commentTo appear in Acta Physics Polonica B39. Considerably extended version of hep-ex/0703003

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Cited by in corpus (13)

• Baryon spectroscopy
• On the cross section ratio sigma_n/sigma_p in eta photoproduction
• Present status on experimental search for pentaquarks
• Mass splittings of SU(3) baryons within a chiral soliton model
• Observation of Narrow $N^{+}(1685)$ and $N^0(1685)$ Resonances in $\gamma N\to \eta \pi N$ Reactions
• Effects of nucleon resonances on $\eta$ photoproduction off the neutron reexamined
• Partial-wave analyses of $\gamma p\to \eta p$ \ and $\gamma n\to \eta n$ using a multichannel framework
• Feasibility study of the $K^{+}d\to K^{0}pp$ reaction for the "${\Theta }^{+}$" pentaquark
• Importance of Mixing for Exotic Baryons
• Search for the $N$(1685) in $\eta \pi$-Photoproduction
• The neutron anomaly in the gamma N --> eta N cross section through the looking glass of the flavour SU(3) symmetry
• Notes on New Narrow N*
• The mass structure of SU(3) baryon antidecuplet and pion muon mass difference