Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On helicity and spin on the light cone   Starting from a one-body front-form equation with Lepage-Brodsky spinors we
show, with a fair amount of new technology, how an integral equation in
standard momentum space with Bjorken-Drell spinors can be obtained. The
integral equation decouples for singlets and triplets.

13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio