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Eta Photoproduction on the proton revisited: Evidence for a narrow N(1685) resonance

V. Kuznetsov·M. V. Polyakov·T. Boiko·J. Jang·A. Kim·W. Kim·A. Ni
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Abstract

Revised analysis of $Σ$ beam asymmetry for $η$ photoproduction on the free proton reveals a resonant structure at $W\sim 1.69$ GeV. Comparison of experimental data with multipole decomposition based on the E429 solution of the SAID partial wave analysis and including narrow states, suggests a narrow ($Γ\leq 15$ MeV) resonance. Possible candidates are $P_{11}$, $P_{13}$, or $D_{13}$ resonances. The result is considered in conjunction with the recent evidence for a bump-like structure at $W\sim 1.67 - 1.68$ GeV in quasi-free $η$ photoproduction on the neutron.

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V. Kuznetsov, M. V. Polyakov, T. Boiko, J. Jang, A. Kim, W. Kim, A. Ni. 2007-03-21. Eta Photoproduction on the proton revisited: Evidence for a narrow N(1685) resonance. https://arxiv.org/abs/hep-ex/0703003

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