Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analytic Computations of Massive One-Loop Amplitudes   We show some new applications of on-shell methods to calculate compact
helicity amplitudes for t tbar production through gluon fusion. The rational
and mass renormalisation contributions are extracted from two independent
Feynman diagram based approaches.

13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol