Constraining the relativistic mean-field models from PREX-2 data: Effective forces revisited

TL;DR

This paper refines relativistic mean-field models using PREX-2 neutron radius data, adjusting specific couplings to improve predictions for finite nuclei, nuclear matter, and neutron star properties, including constraints from GW170817.

Contribution

It introduces new parameter sets for G3 and IOPB-I forces by fine-tuning couplings to better match PREX-2 data without losing predictive accuracy.

Findings

Refitted force parameters reproduce neutron radius of $^{208}$Pb.

Predictions align well with properties of finite nuclei and nuclear matter.

Models are consistent with constraints from neutron star merger observations.

Abstract

Based on the current measurement of the neutron distribution radius ($R_n$) of $^{208}$Pb through the PREX-2 data, we re-visited the recently developed G3 and IOPB-I force parameter by fine-tuning some of the specific couplings within the relativistic mean-field model. The $\omega-\rho-$mesons coupling $\Lambda_{\omega}$ and the $\rho-$meson coupling $g_{\rho}$ are refitted to reproduce the experimental neutron radius of $^{208}$Pb without compromising the bulk properties of finite nuclei and infinite nuclear matter observables. The modified parameter sets are applied to calculate the gross properties of finite nuclei for a few double closed-shell nuclei and further used to obtain the various infinite nuclear matter observables at saturation. In addition to these, the force parameters are adopted to calculate the properties of high isospin asymmetry dense system such as neutron star matter and tested for the validation for the constraint from GW170817 binary neutron star merger events. The tuned forces are predicting relatively good results for finite and infinite nuclear matter systems and the current limitation on neutron radius from PREX-2. A systematic analysis using these two refitted parameter sets over the nuclear chat will be communicated shortly.