Measuring Nuclear Matter Parameters with NICER and LIGO/Virgo

TL;DR

This paper combines NICER and LIGO/Virgo data to constrain the nuclear matter parameter $K_{sym,0}$, providing the most reliable bound to date under standard physics assumptions.

Contribution

It introduces a joint analysis of NICER and LIGO/Virgo measurements to constrain higher-order nuclear matter parameters.

Findings

Derived a joint 1-$\sigma$ constraint on $K_{sym,0}$: -102^{+71}_{-72} MeV.

Established the most reliable bound on $K_{sym,0}$ to date.

Assumed no new physics above saturation density affects neutron star observations.

Abstract

The NICER Collaboration recently reported the measurement of the mass and radius of a pulsar PSR J0030+0451. We here use this new measurement to constrain one of the higher-order nuclear matter parameters $K_{\mathrm{sym,0}}$. We further combine the tidal measurement of the binary neutron star merger GW170817 by LIGO/Virgo to derive a joint 1-$\sigma$ constraint as $K_{\mathrm{sym,0}} = -102^{+71}_{-72}$ MeV. We believe this is the most reliable bound on the parameter to date under the assumption that there is no new physics above the saturation density which impacts neutron star observations.