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arXiv · 0807.2316

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

V. Kuznetsov·M. V. Polyakov·T. Boiko·J. Jang·A. Kim·W. Kim·H. S. Lee·A. Ni·G. -S. Yang
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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.

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V. Kuznetsov, M. V. Polyakov, T. Boiko, J. Jang, A. Kim, W. Kim, H. S. Lee, A. Ni, G. -S. Yang. 2008-07-15. Evidence for a narrow N(1685) resonance in eta photoproduction off the nucleon. https://arxiv.org/abs/0807.2316

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