Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bose-Einstein Correlations of Neutral and Charged Pions in Hadronic Z
  Decays   Bose-Einstein correlations of both neutral and like-sign charged pion pairs
are measured in a sample of 2 million hadronic Z decays collected with the L3
detector at LEP. The analysis is performed in the four-momentum difference
range 300 MeV < Q < 2 GeV. The radius of the neutral pion source is found to be
smaller than that of charged pions. This result is in qualitative agreement
with the string fragmentation model.

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The categories of this paper are: patt-sol
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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: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: math
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: physics
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The categories of this paper are: acc-phys
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The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th