Constraints on the symmetry energy from PREX-II in the multimessenger era

The neutron skin thickness Delta r(np) of heavy nuclei is essentially determined by the symmetry energy density slope L(rho) at rho(c) = 0.11 fm(-3) approximate to 2/3 rho(0) (rho(0) is nuclear saturation density), roughly corresponding to the average density of finite nuclei. The PREX collaboration recently reported a model-independent extraction of Delta r(np)(208) = 0.283 +/- 0.071 fm for the Delta r(np) of Pb-208, suggesting a rather stiff symmetry energy E-sym (rho) with L(rho(c)) >= 52 MeV. We show that the E-sym(rho) cannot be too stiff and L(rho(c)) <= 73 MeV is necessary to be compatible with (1) the ground-state properties and giant monopole resonances of finite nuclei, (2) the constraints on the equation of state of symmetric nuclear matter at suprasaturation densities from flow data in heavy-ion collisions, (3) the largest neutron star (NS) mass reported so far for PSR J0740+6620, (4) the NS tidal deformability extracted from gravitational wave signal GW170817, and (5) the mass-radius of PSR J0030+045 measured simultaneously by NICER. This allows us to obtain 52 <= L(rho(c)) <= 73 MeV and 0.212 <= r208 np <= 0.271 fm and further E-sym (rho(0)) = 34.3 +/- 1.7 MeV, L(rho(0)) = 83.1 +/- 24.7 MeV, and Esym(2 rho(0)) = 62.8 +/- 15.9 MeV. A number of critical implications on nuclear physics and astrophysics are discussed.

Automated summary

This study investigates the impact of symmetry energy density slope on the neutron skin thickness of heavy nuclei and presents important implications for nuclear physics and astrophysics.