Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence for a narrow N(1685) resonance in eta photoproduction off the
  nucleon   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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The categories of this paper are: econ
30
The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
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The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
2
The categories of this paper are: math