Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Double and single pion photoproduction within a dynamical
  coupled-channels model
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci