Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Freeze-Out Parameters in Central 158AGeV Pb+Pb Collisions   Neutral pion production in central 158AGeV Pb+Pb collisions has been studied
in the WA98 experiment at the CERN SPS. The pi0 transverse mass spectrum has
been analyzed in terms of a thermal model with hydrodynamic expansion. The high
accuracy and large kinematic coverage of the measurement allow to limit
previously noted ambiguities in the extracted freeze-out parameters. The
results are shown to be sensitive to the shape of the velocity distribution at
freeze-out.

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The categories of this paper are: quant-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
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The categories of this paper are: stat
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
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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: eess
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio