Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Navigating Around the Algebraic Jungle of QCD: Efficient Evaluation of
  Loop Helicity Amplitudes   A method is developed whereby spinor helicity techniques can be used to
simplify the calculation of loop amplitudes. This is achieved by using the
Feynman-parameter representation where the offending off-shell loop momenta do
not appear. Background Feynman gauge also helps to simplify the calculations.
This method is applicable to any Feynman diagram with any number of loops as
long as the external masses can be ignored, and it is at least as efficient as
the string technique in the special circumstances when the latter can be used.
In order to minimize the very considerable algebra encountered in non-abelian
gauge theories, graphical methods are developed for most of the calculations.
This enables the large number of terms encountered to be organized visually in
the Feynman diagram without the necessity of having to write down any of them
algebraically. A one-loop four-gluon amplitude in a particular helicity
configuration is computed explicity to illustrate the method.

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The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: bayes-an
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The categories of this paper are: supr-con