Recent progress on the determination of the symmetry Energy

TL;DR

This paper reviews recent progress in constraining the symmetry energy's density dependence using laboratory and astrophysical data, highlighting current constraints and challenges at supra-saturation densities.

Contribution

It provides a comprehensive summary of current constraints on symmetry energy parameters and discusses the difficulties in determining its behavior at high densities.

Findings

Symmetry energy at saturation density is approximately 31 ± 2 MeV.

Density slope L is estimated at 50 ± 20 MeV.

Constraining high-density symmetry energy remains a significant challenge.

Abstract

We summarize the current status on constraining the density dependence of the symmetry energy from terrestrial laboratory measurements and astrophysical observations. While the value $E_{sym}({\rho_{0}})$ and density slope $L$ of the symmetry energy at saturation density $\rho_{0}$ can vary largely depending on the data or methods, all the existing constraints are essentially consistent with $E_{sym}({\rho_{0}}) = 31 \pm 2$ MeV and $L = 50 \pm 20$ MeV. The determination of the supra-saturation density behavior of the symmetry energy remains a big challenge.