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

Yao Ma, Jia-Ying Xiong

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 $ω$, $ρ$, $σ$, 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.

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

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 , , , and 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.

Paper Structure

This paper contains 6 sections, 3 equations, 3 figures.

Table of Contents

  1. Introduction
  2. The analysis framework
  3. The Bayesian analysis framework and experimental constraints
  4. A general Walecka-type model for dense nuclear matter
  5. Neutron star structure and sound velocity from the general Walecka-type model
  6. Summary and outlook

Figures (3)

  • Figure 1: The M-R relation for different parameter sets with beta-equilibrium. The constraints PSR J1614-2230, PSR J0348+0432, PSR J0740+6620, J0030+0451, PSR J0437–4715, and PSR J0614–3329 are from Refs. LIGOScientific:2017vwqLIGOScientific:2017yncLIGOScientific:2018ckiSalmi:2024aumVinciguerra:2023qxqChoudhury:2024xbkMauviard:2025dmd, respectively.
  • Figure 2: Sound velocity $v_s^2$ vs. density for various Walecka parameter sets Sugahara:1993wzreinhard1986nuclearLalazissis:1996rdLi:2022okxTodd-Rutel:2005yzoMa:2026kun.
  • Figure 3: Sound velocity and M-R relation for different $b_8$ values in GQHD2.