Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gluon emission at small longitudinal momenta in the QCD effective action
  approach   In the framework of the QCD effective action the vertices of gluon emission
in interaction of reggeons are studied in the limit of small longitudinal
momenta of the emitted gluon. It is found that the vertices drastically
simplify in this limit so that the gluon becomes emitted from a single reggeon
coupled to the projectile and target via multireggeon vertices. Contribution
from this kinematical region is studied for double and 2x2 elementary
collisions inside the composite projectile and target.

4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex