Constraints on the density dependence of the symmetry energy

TL;DR

This paper uses simulations of tin nucleus collisions to constrain how the symmetry energy varies with density, providing insights into nuclear matter properties relevant for astrophysics.

Contribution

It introduces improved Quantum Molecular Dynamics simulations to analyze isospin diffusion and neutron-proton ratios, constraining the density dependence of symmetry energy at sub-normal densities.

Findings

Reproduces isospin diffusion data and neutron/proton spectra ratios

Provides constraints on symmetry energy density dependence at sub-normal densities

Compares results with recent independent analyses

Abstract

Collisions involving 112Sn and 124Sn nuclei have been simulated with the improved Quantum Molecular Dynamics transport model. The results of the calculations reproduce isospin diffusion data from two different observables and the ratios of neutron and proton spectra. By comparing these data to calculations performed over a range of symmetry energies at saturation density and different representations of the density dependence of the symmetry energy, constraints on the density dependence of the symmetry energy at sub-normal density are obtained. Results from present work are compared to constraints put forward in other recent analysis.