Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Isospin symmetry breaking in double-pion production in the region of
  ${d^*(2380)}$ and the scalar ${\sigma}$ meson   The first attempt is made to provide a quantitative theoretical
interpretation of the WASA-at-COSY experimental data on the basic double-pion
production reactions $pn \to d \pi^0\pi^0$ and $pn \to d \pi^+\pi^-$ in the
energy region $T_p =1$ - $1.3$ GeV [P. Adlarson et al., Phys. Lett. B 721, 229
(2013)]. The data are analyzed within a model based on production and decay of
an intermediate $I(J^P)=0(3^+)$ dibaryon resonance $\mathcal{D}_{03}$ (denoted
also as $d^*(2380)$). The observed decrease of the near-threshold enhancement
(the so-called ABC effect) in the reaction $pn \to d \pi^+\pi^-$ in comparison
to that in the reaction $pn \to d \pi^0\pi^0$ is explained (at least partially)
to be due to isospin symmetry violation in the two-pion decay of an
intermediate near-threshold scalar $\sigma$ meson emitted from the
$\mathcal{D}_{03}$ dibaryon resonance under conditions of the partial chiral
symmetry restoration.

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The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: astro-ph
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The categories of this paper are: physics
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The categories of this paper are: hep-th
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The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga