Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On gauge invariance of transverse momentum dependent distributions at
  small x   The interplay between the small x limit of QCD amplitudes and QCD
factorization at moderate x has been studied extensively in recent years. It
was finally shown that semiclassical formulations of small x physics can have
the form of an infinite twist framework involving Transverse Momentum Dependent
(TMD) distributions in the eikonal limit. In this work, we demonstrate that
small x distributions can be formulated in terms of transverse gauge links.
This allows in particular for direct and efficient decompositions of
observables into subamplitudes involving gauge invariant sub-operators which
span parton distributions.

6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics