Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: ttbar production cross section in ppbar collisions at sqrt{s} = 1.8 TeV
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat