Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gluon Condensate from Superconvergent QCD Sum Rule   Sum rules for the nonperturbative piece of correlators (specifically, the
vector current correlator) are discussed. The sum rule subtracting the
perturbative part is of the superconvergent type. Thus it is dominated by the
bound states and low energy production cross section. It leads to a
determination of the gluon condensate of $<\alpha_s G^2> = 0.048 \pm 0.039
GeV^4$

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The categories of this paper are: hep-th
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The categories of this paper are: physics
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The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: quant-ph
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The categories of this paper are: math
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: stat
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The categories of this paper are: cs
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The categories of this paper are: math-ph
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The categories of this paper are: q-alg