Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Obtaining the nuclear gluon distribution from heavy quark decays to
  lepton pairs in p$A$ collisions
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess