Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the non-vanishing of the Collins mechanism for single spin
  asymmetries   The Collins mechanism provides a non-perturbative explanation for the large
single spin asymmetries found in hard semi-inclusive reactions involving a
transversely polarized nucleon. However, there are seemingly convincing reasons
to suspect that the mechanism vanishes, and indeed it does vanish in the naive
parton model where a quark is regarded as an essentially 'free' particle. We
give an intuitive analysis which highlights the difference between the naive
picture and the realistic one, and shows how the Collins mechanism arises when
the quark is described as an off-shell particle by a field in interaction. A
typographical error is corrected in this version.

18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
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The categories of this paper are: eess
20
The categories of this paper are: acc-phys