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Significance of the Sigma Meson in Hadron Physics (QCD) and Possible Experiments to Observe it

Teiji Kunihiro
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Abstract

We first discuss the theoretical and phenomenological significance of the sigma meson ($σ$) in QCD. It is indicated that if the collective modes with the mass 500-600 MeV exists in the $I=J=0$ channel, various empirical facts in hadron physics can be naturally accounted for, which otherwise would remain mysterious. We propose several experiments to produce and detect the $σ$ in nuclei using nuclear and electro-magnetic projectiles. The recent CHAOS data which show a spectral enhancement near the 2 $m_π$ threshold in the $σ$ channel from the reactions A$(π, 2π)$A' where A and A' denotes nuclei is interpreted as a possible evidence of a partial restoration of chiral symmetry in nuclei.

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Teiji Kunihiro. 1999-05-06. Significance of the Sigma Meson in Hadron Physics (QCD) and Possible Experiments to Observe it. https://arxiv.org/abs/hep-ph/9905262

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