Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Heavy quark correlations in hadronic collisions   We discuss results of the $k_t$ - factorization approach for heavy
quark-heavy antiquark correlations in proton-proton and proton-antiproton
collisions for RHIC, Tevatron and LHC. We consider correlations in the
azimuthal angle as well as in the two-dimensional space of transverse momentum
of heavy quark and heavy antiquark. We compare results obtained with the help
of different unintegrated parton distributions (UPDF) from the literature.

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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph