Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Investigating $a_1(1260)$-meson longitudinal twist-2 distribution
  amplitude and $D\to a_1(1260)\ell^+\nu_\ell$ processes within QCD sum rules   In the paper, we study the moments $\langle \xi_{2;a_1}^{\|;n}\rangle$ of the
axial-vector $a_1(1260)$-meson distribution amplitude by using the QCD sum
rules approach under the background field theory. By considering the vacuum
condensates up to dimension-six and the perturbative part up to next-to-leading
order QCD corrections, its first five moments at an initial scale $\mu_0=1~{\rm
GeV}$ are $\langle \xi_{2;a_1}^{\|;2}\rangle|_{\mu_0} = 0.210 \pm 0.018$,
$\langle\xi_{2;a_1}^{\|;4}\rangle|_{\mu_0} = 0.091 \pm 0.007$,
$\langle\xi_{2;a_1}^{\|;6}\rangle |_{\mu_0} = 0.052 \pm 0.004$,
$\langle\xi_{2;a_1}^{\|;8}\rangle |_{\mu_0} = 0.036 \pm 0.003$ and
$\langle\xi_{2;a_1}^{\|;10}\rangle |_{\mu_0} = 0.025 \pm 0.002$, respectively.
We then construct a light-cone harmonic oscillator model for $a_1(1260)$-meson
longitudinal twist-2 distribution amplitude $\phi_{2;a_1}^{\|}(x,\mu)$, whose
input parameters are fitted by using the least square method. As an application
of $\phi_{2;a_1}^\|(x,\mu)$, we calculate the transition form factors (TFFs) of
$D\to a_1(1260)$ in large and intermediate momentum transfers by using the QCD
light-cone sum rules approach. And at the largest recoil point ($q^2=0$), we
obtain $ A(0) = 0.130_{ - 0.015}^{ + 0.013}$, $V_1(0) =
1.900_{-0.125}^{+0.121}$, $V_2(0) = 0.210_{-0.020}^{ + 0.018}$, and $V_0(0) =
0.236_{ - 0.024}^{ + 0.026}$. By applying the extrapolated TFFs to the
semi-leptonic decay $D^{0(+)} \to a_1^{-(0)}(1260)\ell^+\nu_\ell$, we obtain
${\cal B}(D^0\to a_1^-(1260) e^+\nu_e) = (5.458_{-0.681}^{+0.720}) \times
10^{-5}$, ${\cal B}(D^+\to a_1^0(1260) e^+\nu_e) = (6.922_{-0.864}^{+0.913})
\times 10^{-5}$, ${\cal B}(D^0\to a_1^-(1260) \mu^+
\nu_\mu)=(4.897_{-0.627}^{+0.663}) \times 10^{-5}$, ${\cal B}(D^+ \to
a_1^0(1260) \mu^+ \nu_\mu)=(6.210_{-0.796}^{+0.767}) \times 10^{-5}$.

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The categories of this paper are: astro-ph
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The categories of this paper are: math-ph
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The categories of this paper are: stat
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The categories of this paper are: hep-th
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The categories of this paper are: cs
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The categories of this paper are: comp-gas
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The categories of this paper are: econ
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: eess
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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int