Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pion Helicity Structure And Its Consequence For The Hard Scattering Form
  Factor   In a study of the elastic pion form factor for large momentum transfers based
on a modified perturbative QCD (PQCD) approach we have included helicity
components that are customarily neglected. Along with the inclusion of
transverse momentum, this gives a large suppression of the form factor from the
prediction of the original hard scattering model based on PQCD in the $Q^{2}$
domain where experimental data are available. We conclude that nonperturbative
contributions will dominate in this region.

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The categories of this paper are: econ
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: physics
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
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The categories of this paper are: cs