Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of the semileptonic b branching fractions and average b
  mixing parameter in Z decays   The semileptonic branching fractions for primary and cascade b decays BR(b ->
lepton-), BR(b -> c -> lepton+) and BR(b -> cbar -> lepton-) were measured in
hadronic Z decays collected by the DELPHI experiment at LEP.
  The sample was enriched in b decays using the lifetime information and
various techniques were used to separate leptons from direct or cascade b
decays.
  By fitting the momentum spectra of di-leptons in opposite jets, the average b
mixing parameter chi-bar was also extracted.
  The following results have been obtained:
  BR(b -> lepton-) = (10.70 +/- 0.08 (stat) +/- 0.21
(syst)_{+0.44}^{-0.30}(model))%
  BR(b -> c -> lepton+) = (7.98 +/- 0.22 (stat) +/- 0.21
(syst)^{+0.14}_{-0.20}(model))%
  BR(b -> cbar -> lepton-) = (1.61 +/- 0.20 (stat) +/- 0.17
(syst)^{+0.30}_{-0.44}(model))% chi-bar = 0.127 +/- 0.013 (stat) +/- 0.005
(syst) +/- 0.004(model)

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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
19
The categories of this paper are: eess
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The categories of this paper are: quant-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: funct-an