Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Poincar\'e subalgebra and gauge invariance in nucleon structure   By separating the gluon field into physical and pure-gauge components, the
usual Poincar\'e subalgebra for an interacting system can be reconciled with
gauge-invariance when decomposing the total rotation and translation generators
of QCD into quark and gluon parts. The gauge-invariant quark/gluon parts act as
the generators for the gauge-invariant physical component of the quark/gluon
field, not the full quark/gluon field which also contains the gauge degrees of
freedom. We clarify that the naive canonical decomposition of generators, while
trivially respecting the Poincar\'e subalgebra, might not give a completely
gauge-invariant quark-gluon structure of the nucleon momentum and spin, though
limited invariance within a certain gauge class can be proven.

23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex