Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of the Branching Ratio B(D+ --> rho^0 l nu)/B(D+ --> K*0 l
  nu)   We report a measurement of the branching ratio B(D+-->rho^0 l nu)/ B(D+-->K*0
l nu) from the Fermilab charm hadroproduction experiment E791. Based on signals
of 49+-17 events in the D+--> rho^0 e nu mode and 54+-18 events in the D+-->
rho^0 mu nu mode, we measure B(D+-->rho^0 e nu)/B(D+-->K*0 e nu) =
0.045+-0.014+-0.009, and B(D+-->rho^0 mu nu)/B(D+-->K*0 mu nu) =
0.051+-0.015+-0.009. Combining the results from both the electronic and muonic
modes, we obtain B(D+-->rho^0 l nu)/B(D+-->K*0 l nu) = 0.047+-0.013. This
result is compared to theoretical predictions.

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The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
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The categories of this paper are: q-bio
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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc
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The categories of this paper are: physics
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg