Neutron star structure and nuclear matter properties from a general Walecka-type model with Bayesian analysis

TL;DR

This paper develops a Bayesian framework using a Walecka-type model to analyze dense nuclear matter and neutron star properties, revealing a peak in sound velocity linked to meson mixing.

Contribution

It introduces a Bayesian analysis approach with a general Walecka model to explain sound velocity peaks in neutron stars without phase transitions.

Findings

Pure hadronic models can produce sound velocity peaks via meson mixing.

The model successfully describes nuclear matter properties and neutron star observations.

Provides a new perspective on the origin of sound velocity peaks in dense matter.

Abstract

We establish a Bayesian analysis framework with a general Walecka-type relativistic mean-field model to study dense nuclear matter under constraints from nuclear matter properties and neutron star observations. With experimental and observational data well described, we find that pure hadronic descriptions can generate a peak structure in sound velocity by $\omega$, $\rho$, $\sigma$, and $a_0$ meson mixing, which is crucial for describing both medium and massive neutron stars. As the peak structure is frequently interpreted as a signature of phase transitions, our findings provide a new perspective on the microscopic origin of the sound velocity peak just with pure hadronic matter.