Implications of the empirical neutron-star mass formula in constraining the parameters of the nuclear equation of state
Abstract
The integration of multiple datasets has emerged as an effective method for constraining the equation of state of nuclear matter. The empirical mass formula of neutron stars establishes a correlation between astrophysical and ground-based laboratory observations, providing a convenient framework for related investigations. In this study, based on experimental data of the neutron skin thickness and dipole polarizability of ^208Pb, we estimate the posterior probability distributions of the parameters of the equation of state of nuclear matter, neutron star radius, tidal deformability, and gravitational redshift within the theoretical framework of neutron star models and Bayesian statistical methods.The results show that the empirical mass formula of neutron stars considerably influences the constraint of the equation of state of nuclear matter. The neutron skin thickness data exhibit a comparable constraining effect to neutron star radius observations. Based on the neutron skin thickness data released by the PREX-II Collaboration, the empirical mass formula supports a stiffer equation of state for nuclear matter than these from the neutron star radius observations.By calculating the posterior probability distribution of the gravitational redshift for a normal neutron star, there is a substantial likelihood that the mass of the source GS1826-24 is found to be approximately 1.4 times the solar mass. Combining neutron star radius observations with the joint data of the neutron skin thickness and dipole polarizability of ^208Pb, it is evident that,neutron star radius and dipole polarizability data play a more crucial role than neutron skin thickness data, in constraining the parameters of the equation of state of nuclear matter.The dipole polarizability data of ^208Pb demonstrate the most optimal constraint effect, highlighting the significance of rich and precise experimental data in addressing the intricate problem of the equation of state of nuclear matter.
