Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Decay constants of the pseudoscalar mesons in the framework of the
  coupled Schwinger-Dyson equation and Bethe-Salpeter equation   In this article, we investigate the structures of the pseudoscalar mesons
($\pi$, $K$, $D$, $D_s$, $B$ and $B_s$) in the framework of the coupled rainbow
Schwinger-Dyson equation and ladder
  Bethe-Salpeter equation with the confining effective potential (infrared
modified flat bottom potential).
  The Schwinger-Dyson functions for the $u$, $d$ and $s$ quarks are greatly
renormalized at small momentum region and the curves are steep at about
$q^2=1GeV^2$ which indicates an explicitly dynamical symmetry breaking. The
Euclidean time fourier transformed quark propagators have no mass poles in the
time-like region which naturally implements confinement. As for the $c$ and $b$
quarks, the current masses are very large, the renormalization are more tender,
however, mass poles in the time-like region are also absent. The Bethe-Salpeter
wavefunctions for those mesons have the same type (Gaussian type) momentum
dependence and center around small momentum which indicate that the bound
states exist in the infrared region. The decay constants for those pseudoscalar
mesons are compatible with the values of experimental extractions and
theoretical calculations, such as lattice simulations and QCD sum rules.

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The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
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The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: eess
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: math
3
The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: q-bio
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The categories of this paper are: adap-org