Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The six-quark structure of long-lived $D$-mesons and $\psi/J$   The harmonic quarks are applied to the analysis of quark structures of
long-lived $D$-mesons and $\psi/J$. In the harmonic quark model the quarks of
long-lived mesons ($\pi^0$, $\pi^\pm$, $K^\pm$, $K^0$, $B^0$, $B^\pm$) are
weakly relativistic objects with the excess energy of valent quarks less than 7
MeV. In contrast to this, the long-lived $D$-mesons in two-quark standard have
the apparent excess energies of a few hundred MeV. It was established that all
long-lived $D$-mesons and $\psi/J$ have the six-quark structures. There are two
valent quarks and two additional neutral quark-antiquark $u$-pairs. The quark
structures of $D^0$, $D^\pm$, $D_s^\pm$ and $\psi/J$ are given. The excess
energies of six-quark $D$-mesons also does not exceed 7 MeV. A six-color quark
composition and the absence of two-quark $D$-mesons in the context of QCD are
discussed.

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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
18
The categories of this paper are: econ
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The categories of this paper are: mtrl-th
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The categories of this paper are: atom-ph
3
The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: astro-ph
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The categories of this paper are: eess
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The categories of this paper are: math-ph
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The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int