Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of a Structure in $pp \to pp\gamma\gamma$ near the $\pi\pi$
  Threshold and its Possible Interpretation by $\gamma\gamma$ Radiation from
  Chiral Loops in the Mesonic $\sigma$ Channel
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat