Locations at Which Nuclear Matter Properties Are Most Sensitive to Density in Neutron Stars

Different experimental measurements of nuclei probe different densities relevant to neutron star matter, making them sensitive to distinct regions within a neutron star at varying distances from the core. The bulk properties of neutron stars, such as radius and moment of inertia, depend on integrals over the density profiles, emphasizing the importance of understanding where within the star nuclear parameters exert the greatest influence. Nuclear matter within neutron stars can be characterized by parameters related to the symmetry energy and the symmetric matter equation of state, each with simple physical interpretations. We conducted a precision study to identify which regions of the neutron star are most sensitive to variations in these parameters. Using thousands of neutron star models constructed from nuclear matter with systematically varied parameter sets, we performed correlation analysis and principal component analysis between nuclear matter parameters and local densities throughout the star. This allows us to map the sensitivity of each parameter to specific radial locations and connect these regions back to nuclear observables.