Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin effects in vector meson production at LEP   Spin observables may reveal much deeper properties of non perturbative
hadronic physics than unpolarized quantities. We discuss the polarization of
hadrons produced in $e^+e^-$ annihilation at LEP. We show how final state $q
\bar q$ interactions may give origin to non zero values of the off-diagonal
element $\rho^{\,}_{1,-1}$ of the helicity density matrix of vector mesons:
some predictions are given for $K^*, \phi, D^*$ and $B^*$ in agreement with
recent OPAL data. We also discuss the relative amount of vector and
pseudovector meson states and the probability of helicity zero vector states.
Similar measurements in other processes are suggested.

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The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: chao-dyn
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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: chem-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: hep-ex
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ