Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quark Model Description of Polarised Deep Inelastic Scattering and the
  prediction of $g_2$   We show how the operator product expansion evaluated in the approximation of
ignoring gluons leads to the covariant formulation of the quark parton model.
We discuss the connection with other formulations and show how the free quark
model prediction, $g_2=0$, changes smoothly into the Wandzura-Wilczek (WW)
relation for quark masses small relative to the nucleon mass. Previous
contradictory parton model predictions are shown to follow from an inconsistent
treatment of the mass shell conditions. The description is extended to include
quark mass corrections.

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The categories of this paper are: hep-lat
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph