Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $|V_{cb}|$ from OPE Sum Rules for Heavy Flavor Transitions   We derive a model-independent upper bound for the axial-vector form factor of
the $B\ra D^*$ transition at zero recoil, $F_{B\ra D^*}$. The form factor turns
out to be noticeably less than unity. The deviation of $F_{B\ra D^*}$ from
unity is larger than previously anticipated. Using our estimate we extract
$|V_{cb}|$ from the measured exclusive rate of $B\ra D^* l\nu$ extrapolated to
the point of zero recoil. The central `` exclusive" value of $|V_{cb}|$ is in
agreement with the value obtained from the inclusive semileptonic width $\Gamma
(B\ra X_c l\nu)$. We argue that the theoretical uncertainty in determining
$|V_{cb}|$ from the total inclusive width is significantly reduced if a
constraint on the quark mass difference $m_b - m_c$ stemming from the heavy
quark expansion is taken into account.

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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: mtrl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-lat
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The categories of this paper are: atom-ph