Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measuring the Longitudinally Polarized Proton Gluon Distribution using
  Photoproduction Processes   Little information is known about the polarization of gluons inside a
longitudinally polarized proton. We investigate the sensitivity of
photoproduction experiments with both beam and target longitudinally polarized
to the polarization of the gluon distribution in the proton. We study the
photoproduction of jets and heavy quarks and conclude that they are both
sensitive to the gluon polarization.

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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: math
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The categories of this paper are: hep-th
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The categories of this paper are: supr-con
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
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The categories of this paper are: cond-mat
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The categories of this paper are: cs