Thermal Properties of Asymmetric Nuclear Matter

TL;DR

This paper investigates the thermal properties of asymmetric nuclear matter using a relativistic mean-field approach, revealing significant effects of isovector-scalar self-energies on phase transitions across various densities, asymmetries, and temperatures.

Contribution

It introduces a self-consistent density-dependent meson-baryon vertex model incorporating isovector-scalar self-energies, highlighting their impact on nuclear matter phase behavior.

Findings

Isovector-scalar self-energies significantly alter thermal properties.

Phase transitions are modified when isovector-scalar self-energies are included.

The model covers densities up to neutron star regimes and temperatures up to 100 MeV.

Abstract

The thermal properties of asymmetric nuclear matter are investigated in a relativistic mean- field approach. We start from free space NN-interactions and derive in-medium self-energies by Dirac-Brueckner theory. By the DDRH procedure we derive in a self-consistent approach density- dependent meson-baryon vertices. At the mean-field level, we include isoscalar and isovector scalar and vector interactions. The nuclear equation of state is investigated for a large range of total baryon densities up to the neutron star regime, the full range of asymmetries from symmetric nuclear matter to pure neutron matter, and temperatures up to T~100 MeV. The isovector-scalar self-energies are found to modify strongly the thermal properties of asymmetric nuclear matter. A striking result is the change of phase transitions when isovector-scalar self-energies are included.