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arXiv · 2505.24674

Review on recent progress in the study of the $N^*(920)$ subthreshold singularity and the $\sigma/f_0(500)$ meson

Qu-Zhi Li·Zhiguang Xiao·Han-Qing Zheng
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Abstract

We summarize recent results on studies of $\pi\pi$ and $\pi N$ scatterings. They include the finding of a negative-parity nucleon pole with a mass lower than the nucleon mass, and the pole trajectory of $f_0(500)$ as the pion mass varies. The results are obtained from model-independent dispersion analyses. We also study the thermal properties of $f_0(500)$ based on the $O(N)$ $\sigma$ model and $N/D$ method.

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Qu-Zhi Li, Zhiguang Xiao, Han-Qing Zheng. 2025-05-30. Review on recent progress in the study of the $N^*(920)$ subthreshold singularity and the $\sigma/f_0(500)$ meson. https://doi.org/10.1140/epjs%2Fs11734-025-02022-y

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