Decay of a scalar $\sigma$-meson near the critical end-point in the PNJL model

TL;DR

This paper investigates the behavior and decay properties of the scalar sigma meson near the critical end-point in the QCD phase diagram using the PNJL model, highlighting nonthermal decay width enhancement.

Contribution

It provides a detailed analysis of the sigma meson decay width near the critical end-point within the PNJL model, including temperature dependence and comparison with experimental data.

Findings

Decay width increases nonthermally near the critical end-point.

Strong coupling constant $g_{\sigma\pi\pi}$ aligns with experimental data.

Decay condition $m_\sigma \geq 2m_\pi$ is broken near the critical end-point.

Abstract

Properties of a scalar $\sigma$-meson are investigated in the two-flavor Nambu-Jona-Lasinio model with the Polyakov loop. Model analysis of the phase diagram of strong interacting matter is performed. The temperature dependence of the $\sigma\rightarrow\pi\pi$ decay width is studied at the zero chemical potential and near the critical end-point. The calculated strong coupling constant $g_{\sigma\pi\pi}$ and the decay width are compared with available experimental data and other model results. Nonthermal enhancement of the total decay width is noted for the $\sigma$ meson near the critical end-point when the condition $m_\sigma\geq2m_\pi$ is broken.