Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Impact of future HERA data on the determination of proton parton
  distribution functions using the ZEUS QCD fit   The high precision and large kinematic coverage of the data from the HERA-I
running period (1994-2000) have already allowed precise extractions of proton
parton distribution functions (PDFs). The HERA-II running program is now
underway and is expected to provide a substantial increase in the luminosity
collected at HERA. In this paper, a study is presented which investigates the
potential impact of future data from HERA on the proton PDF uncertainties,
within the currently planned running scenario. In addition, the effect of a
possible future measurement of the longitudinal structure function, FL, on the
gluon distribution is investigated.

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The categories of this paper are: gr-qc
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The categories of this paper are: physics
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The categories of this paper are: math
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: ao-sci
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph