Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Neutral pion and $\eta$ meson production at mid-rapidity in Pb-Pb
  collisions at $\sqrt{s_{NN}}$ = 2.76 TeV
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
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
36
The categories of this paper are: cmp-lg