Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generalized Parton Distributions of Pions. Spin Structure of Hadrons   We present an extensive study on generalized parton distributions of pions.
In particular, we present the results for the pion-photon transition
distribution amplitudes in the Nambu - Jona-Lasinio model. We discuss the
phenomenology of such objects and give explicit estimates for cross sections.
The spin structure of the proton is also studied: we discuss the results for
the T-odd transverse momentum distributions in quark models.

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The categories of this paper are: mtrl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
2
The categories of this paper are: math
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The categories of this paper are: hep-ex
1
The categories of this paper are: cs
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The categories of this paper are: quant-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
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The categories of this paper are: patt-sol