Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Study of Spin Alignment of rho(770)+- and omega(782) Mesons in
  Hadronic Z Decays   The helicity density matrix elements rho[00] of rho(770)+- and omega(782)
mesons produced in Z decays have been measured using the OPAL detector at LEP.
Over the measured meson energy range, the values are compatible with 1/3,
corresponding to a statistical mix of helicity -1, 0 and +1 states. For the
highest accessible scaled energy range 0.3 < x_E < 0.6, the measured rho[00]
values of the rho(770)+- and the omega are 0.373 +- 0.052 and 0.142 +- 0.114,
respectively. These results are compared to measurements of other vector
mesons.

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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom