Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Measurements of top-quark pair spin correlations in the $e\mu$ channel
  at $\sqrt{s} = 13$ TeV using $pp$ collisions in the ATLAS detector
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph