Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Eta photoproduction off the neutron at GRAAL: Evidence for a resonant
  structure at W=1.67 GeV   New (preliminary) data on eta photoproduction off the neutron are presented.
These data reveal a resonant structure at W=1.67 GeV.

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The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
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The categories of this paper are: cond-mat
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs