Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Search for $B^{0} \to \tau^\pm \ell^\mp$ ($\ell=e,\mu$) with a hadronic
  tagging method at Belle   We present a search for the lepton-flavor-violating decays $B^{0} \to
\tau^\pm \ell^\mp$, where $\ell=(e,\,\mu)$, using the full data sample of $772
\times 10^6$ $B \overline{B}$ pairs recorded by the Belle detector at the KEKB
asymmetric-energy $e^+e^-$ collider. We use events in which one $B$ meson is
fully reconstructed in a hadronic decay mode. The $\tau^\pm$ lepton is
reconstructed indirectly using the momentum of the reconstructed $B$ and that
of the $\ell^\mp$ from the signal decay. We find no evidence for $B^{0} \to
\tau^\pm \ell^\mp$ decays and set upper limits on their branching fractions at
90% confidence level of $\cal B$($B^{0} \to \tau^\pm \mu^{\mp}$)$ < 1.5 \times
10^{-5}$ and $\cal B$($B^{0} \to \tau^\pm e^{\mp}$)$ < 1.6 \times 10^{-5}$.

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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
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The categories of this paper are: astro-ph
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
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The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: chem-ph