Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of the Lepton Forward-Backward Asymmetry in $B \rightarrow
  X_s \ell^+ \ell^-$ Decays with a Sum of Exclusive Modes   We report the first measurement of the lepton forward-backward asymmetry
${\cal A}_{\rm FB}$ as a function of the squared four-momentum of the dilepton
system, $q^2$, for the electroweak penguin process $B \rightarrow X_s \ell^+
\ell^-$ with a sum of exclusive final states, where $\ell$ is an electron or a
muon and $X_s$ is a hadronic recoil system with an $s$ quark. The results are
based on a data sample containing $772\times10^6$ $B\bar{B}$ pairs recorded at
the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB $e^+ e^-$
collider. ${\cal A}_{\rm FB}$ for the inclusive $B \rightarrow X_s \ell^+
\ell^-$ is extrapolated from the sum of 10 exclusive $X_s$ states whose
invariant mass is less than 2 GeV/$c^2$. For $q^2 > 10.2$ GeV$^2$/$c^2$, ${\cal
A}_{\rm FB} < 0$ is excluded at the 2.3$\sigma$ level, where $\sigma$ is the
standard deviation. For $q^2 < 4.3$ GeV$^2$/$c^2$, the result is within
1.8$\sigma$ of the Standard Model theoretical expectation.

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The categories of this paper are: q-bio
3
The categories of this paper are: physics
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
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The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: dg-ga