Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Color-factor symmetry and BCJ relations for QCD amplitudes   Tree-level $n$-point gauge-theory amplitudes with $n-2k$ gluons and $k$ pairs
of (massless or massive) particles in the fundamental (or other) representation
of the gauge group are invariant under a set of symmetries that act as
momentum-dependent shifts on the color factors in the cubic decomposition of
the amplitude. These symmetries lead to gauge-invariant constraints on the
kinematic numerators. They also directly imply the BCJ relations among the
Melia-basis primitive amplitudes previously obtained by Johansson and Ochirov.

16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an