Sensitivity of neutron star observables to microscopic nuclear parameters of realistic equations of state

TL;DR

This paper analyzes how neutron star observables are sensitive to microscopic nuclear parameters within the Chiral-Mean-Field model, identifying key parameters that influence observable properties like mass and radius through a Fisher-information approach.

Contribution

It introduces a Fisher-inspired sensitivity analysis framework to quantify the influence of nuclear parameters on neutron star observables, guiding future nuclear inference from astrophysical data.

Findings

The three most influential nuclear parameters are the vacuum dilaton field value, scalar singlet strength, and the quadratic scalar term.

The sensitivity ranking of parameters is mildly dependent on the specific observable.

The framework enables a data-driven, reproducible assessment of parameter impacts in dense-matter models.

Abstract

The equation of state of matter at supranuclear densities governs the astrophysical observables of neutron stars. A realistic, though complex, description is provided by the Chiral-Mean-Field model, which depends on many microscopic nuclear-physics parameters. We present a Fisher-information-inspired analysis of the sensitivity of neutron-star observables to the parameters of the Chiral-Mean-Field model at $\beta$-equilibrium using SLy as a crust. We then compute neutron-star sequences and extract masses, radii, compactnesses, and tidal deformabilities. From the logarithmic derivatives of these observables with respect to each nuclear parameter, we construct a dimensionless, Fisher-inspired sensitivity matrix and perform a principal-component analysis to identify the effective combinations of nuclear parameters that most strongly affect neutron-star observables. Although the ranking depends mildly on the observable, the three most important nuclear parameters are the vacuum value of the dilaton field $\chi_0$ (which sets the overall scale of the scalar potential and trace-anomaly contribution), the scalar singlet strength $g_{1}^X$ (which controls the overall scalar attraction through the baryon effective masses), and the $k_0$ quadratic scalar term (which governs the curvature of the scalar potential). This framework provides a reproducible, data-driven approach to quantify parameter sensitivities in dense-matter models and to guide future Bayesian inference of nuclear information from multi-messenger astrophysical observations.