Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Gerasimov-Drell-Hearn sum rule and the single-pion photoproduction
  multipole E0+ close to threshold   The long-standing discrepancy between the Gerasimov-Drell-Hearn sum rule and
the analysis of pion photoproduction multipoles is greatly diminished by use of
s-wave multipoles that are in accord with the predictions of chiral
perturbation theory and describe the experimental data in the threshold region.
The remaining difference may be due to contributions of channels with more
pions and/or heavier mesons whose contributions to the sum rule remain to be
investigated by a direct measurement of the photoabsorption cross sections.

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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
16
The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
1
The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
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The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph