Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exclusive double quarkonium production and generalized TMDs of gluons   Being the "mother distributions" of all types of two-parton correlation
functions, generalized transverse momentum dependent parton distributions
(GTMDs) have attracted a lot of attention over the last years. We argue that
exclusive double production of pseudoscalar quarkonia ($\eta_c$ or $\eta_b$) in
nucleon-nucleon collisions gives access to GTMDs of gluons.

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The categories of this paper are: mtrl-th
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The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: plasm-ph
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The categories of this paper are: physics
1
The categories of this paper are: cs
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
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The categories of this paper are: q-bio
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga