Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Chemical relaxation time of pions in hot hadronic matter   We calculate characteristic time scales for chemical equilibration of pions
in hot hadronic matter using an effective chiral Lagrangian. We find that
inelastic processes involving the vector and axial vector mesons reduce the
chemical equilibration time by a factor of $\sim 10$ compared to the result
previously calculated in chiral perturbation theory. For a temperature of
$T\sim 150 MeV$ we obtain a chemical relaxation time of $\tau_{ch} \simeq 10
fm/c$, which is comparable with typical time scales for a hadronic system
generated in SPS-energy heavy ion collisions. The effect of baryons is also
estimated and found to be negligible for SPS-energies but important for
AGS-energies. We predict, that chemical freeze-out should take place at
considerable higher temperatures $\Delta T \simeq 20 MeV$ than thermal
freeze-out and that the hadronic phase would not sustain a pion chemical
potential larger than $100 MeV$.

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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th