Constraints on Skyrme Equations of State from Doubly Magic Nuclei, Ab-Initio Calculations of Low-Density Neutron Matter, and Neutron Stars

TL;DR

This paper constrains Skyrme energy-density functional parameters using nuclear, neutron matter, and neutron star data, revealing the importance of neutron effective mass in predicting neutron star maximum mass and radius.

Contribution

It introduces a constrained family of Skyrme parameters consistent with nuclear and astrophysical observations, emphasizing the role of neutron effective mass.

Findings

Maximum neutron star mass of 2.1 solar masses with effective mass 0.60-0.65

Predicted radius of 12.4 km for a 1.4 solar mass neutron star

Neutron effective mass significantly influences neutron star maximum mass

Abstract

We use properties of doubly-magic nuclei, ab-initio calculations of low-density neutron matter, and of neutron stars to constrain the parameters of the Skyrme energy-density functional. We find all of these properties can be reproduced within a constrained family of Skyrme parameters. The maximum mass of a neutron star is found to be sensitive to the neutron effective mass. A value of [$ m^{*}_{\rm n}/m](\rho_0) = 0.60-0.65 $ is required to obtain a maximum neutron star mass of 2.1 solar masses. Using the constrained Skyrme functional with the aforementioned effective mass, the predicted radius for a neutron star of 1.4 solar masses is 12.4(1) km and $\Lambda$ = 423(40).