Abstract

Relativistic mean-field models are successfully used for the description of finite nuclei and nuclear matter. Approaches with density-dependent meson-nucleon couplings assume specific functional forms and a dependence on vector densities in most cases. In this work, parametrizations with a larger sample of functions and dependencies on vector and scalar densities are investigated. They are obtained from fitting properties of finite nuclei. The quality of the description of nuclei and the obtained equations of state of symmetric nuclear matter and neutron matter below saturation are very similar. However, characteristic nuclear matter parameters, the equations of state and the symmetry energy at suprasaturation densities show some correlations with the choice of the density dependence and functional form of the couplings. Conditions are identified that can lead to problems for some of the parametrizations.

Highlights

  • A realistic description of dense matter is essential for the physics of compact stars and the simulation of core-collapse supernovae and neutron-star mergers; see, e.g., [1] for details

  • The theoretical description of nuclei and nuclear matter in the present relativistic mean-field (RMF) approach proceeds in the usual way as presented, e.g., in [8]

  • The results clearly show that a fit of parametrizations to properties of finite nuclei fix the equation of state (EoS) at sub-saturation densities fairly well, but the extrapolation to higher densities depends strongly on the functional form of the couplings and the choice of the argument, i.e., whether a scalar or vector density dependence is used

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Summary

Introduction

A realistic description of dense matter is essential for the physics of compact stars and the simulation of core-collapse supernovae and neutron-star mergers; see, e.g., [1] for details. The parameters of the density dependence are customarily determined by applying the EDF to the description of finite nuclei and by fitting to a selected set of their properties. A particular property of RMF models is the occurrence of two different particle number densities: vector densities and scalar densities Their interplay is essential to describe the saturation of nuclear matter in the model. The first self-consistent RMF model with density-dependent couplings that were fitted to properties of finite nuclei used the so-called vector density in the couplings and specific forms for the functional dependence [8]. The aim of this work is a comparison of RMF models and the corresponding nuclear matter EoSs with DD couplings of different functional form and dependencies on vector and scalar densities that were fitted to the same set of nuclear observables.

RMF Model with Density-Dependent Couplings
Lagrangian Density and Energy Density Functional
Homogeneous Nuclear Matter
Finite Nuclei
Parametrization of Couplings
Determination of Parameters and Couplings
Properties of Nuclear Matter and Equation of State
Nuclear Matter Parameters
Equation of State and Symmetry Energy
Constraints on the Density Dependence of the Couplings
Conclusions and Outlook
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