Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: J/Psi Polarization in 800-GeV p-Cu Interactions   We present measurements of the polarization of the $ J/\psi $ produced in
800-GeV proton interactions with a copper target. Polarization of the $ J/\psi
$ is sensitive to the $ c \bar{c} $ production and hadronization processes. A
longitudinal polarization is observed at large $ x_{F} $, while at small $
x_{F} $ the state is produced essentially unpolarized or slightly transversely
polarized. No significant variation of the polarization is observed versus $
p_{T} $.

25
The categories of this paper are: patt-sol
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The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
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The categories of this paper are: q-alg
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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: nlin
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph