# Measurement of the nuclear symmetry energy parameters from gravitational wave events

## TL;DR

This paper uses gravitational wave data from GW170817 to constrain nuclear symmetry energy parameters, especially the slope L_0, revealing lower values than previously reported and providing new insights into nuclear matter properties.

## Contribution

It introduces novel constraints on the symmetry energy parameters from gravitational wave observations, focusing on the slope L_0 and deriving bounds on higher-order nuclear terms.

## Key findings

- Gravitational wave data are sensitive to the slope L_0 of the symmetry energy.
- The analysis favors lower L_0 values around 20 MeV.
- New analytic constraints on higher-order nuclear symmetry energy terms.

## Abstract

The nuclear symmetry energy plays a role in determining both the nuclear properties of terrestrial matter as well as the astrophysical properties of neutron stars. The first measurement of the neutron star tidal deformability, from gravitational wave event GW170817, provides a new way of probing the symmetry energy. In this work, we report on new constraints on the symmetry energy from GW170817. We focus in particular on the low-order coefficients: namely, the value of the symmetry energy at the nuclear saturation density, S_0, and the slope of the symmetry energy, L_0. We find that the gravitational wave data are relatively insensitive to S_0, but that they depend strongly on L_0 and point to lower values of L_0 than have previously been reported, with a peak likelihood near L_0 ~ 20 MeV. Finally, we use the inferred posteriors on L_0 to derive new analytic constraints on higher-order nuclear terms.