Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Precise determination of the CKM matrix element $\left| V_{cb}\right|$
  with $\bar B^0 \to D^{*\,+} \, \ell^- \, \bar \nu_\ell$ decays with hadronic
  tagging at Belle   The precise determination of the CKM matrix element $\left| V_{cb}\right|$ is
important for carrying out tests of the flavour sector of the Standard Model.
In this article we present a preliminary analysis of the $\bar B^0 \to D^{*\,+}
\, \ell^- \, \bar \nu_\ell$ decay mode and its charge conjugate, selected in
events that contain a fully reconstructed $B$-meson, using 772 million $e^+ \,
e^- \to \Upsilon(4S) \to B \bar B$ events recorded by the Belle detector at
KEKB. Unfolded differential decay rates of four kinematic variables fully
describing the $\bar B^0 \to D^{*\,+} \, \ell^- \, \bar \nu_\ell$ decay in the
$B$-meson rest frame are presented. We measure the total branching fraction
$\mathcal{B}( \bar B^0 \to D^{*\,+} \, \ell^- \, \bar \nu_\ell ) = \left(4.95
\pm 0.11 \pm 0.22 \right) \times 10^{-2}$, where the errors are statistical and
systematic respectively. The value of $\left|V_{cb} \right|$ is determined to
be $\left( 37.4 \pm 1.3 \right) \times 10^{-3}$. Both results are in good
agreement with current world averages.

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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
16
The categories of this paper are: stat
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin