Symmetry energy constraints from GW170817 and laboratory experiments

TL;DR

This paper combines gravitational wave data from GW170817 with laboratory nuclear experiments to constrain the symmetry energy component of neutron star matter, providing insights into the internal structure of neutron stars.

Contribution

It introduces a method to extract symmetry pressure by integrating astrophysical and laboratory data, improving understanding of nuclear matter under extreme conditions.

Findings

Symmetry pressure constrained over a density range from 1.2 to 4.5 times nuclear saturation density.

Uncertainties in symmetry pressure are currently large but can be reduced with future data.

Demonstrates the potential of combined astrophysical and experimental approaches to study nuclear matter.

Abstract

The LIGO-Virgo collaboration detection of the binary neutron-star merger event, GW170817, has expanded efforts to understand the Equation of State (EoS) of nuclear matter. These measurements provide new constraints on the overall pressure, but do not elucidate its origins, by not distinguishing the contribution to the pressure from symmetry energy which governs much of the internal structure of a neutron star. By combining the neutron star EoS extracted from the GW170817 event and the EoS of symmetric matter from nucleus-nucleus collision experiments, we extract the symmetry pressure, which is the difference in pressure between neutron and nuclear matter over the density region from 1.2$\rho_{0}$ to $4.5\rho_{0}$. While the uncertainties in the symmetry pressure are large, they can be reduced with new experimental and astrophysical results.