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

Abstract

The neutron skin thickness Δr_{np} of heavy nuclei is essentially determined by the symmetry energy density slope L(ρ) at ρ_{c}=0.11fm^{−3}≈2/3ρ_{0} (ρ_{0} is nuclear saturation density), roughly corresponding to the average density of finite nuclei. The PREX collaboration recently reported a model-independent extraction of Δr_{np}^{208}=0.283±0.071 fm for the Δr_{np} of ^{208}Pb, suggesting a rather stiff symmetry energy E_{sym}(ρ) with L(ρ_{c})≥52 MeV. We show that the E_{sym}(ρ) cannot be too stiff and L(ρ_{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(ρ_{c})≤73 MeV and 0.212≤Δr_{np}^{208}≤0.271 fm and further E_{sym}(ρ_{0})=34.3±1.7 MeV, L(ρ_{0})=83.1±24.7 MeV, and E_{sym}(2ρ_{0})=62.8±15.9 MeV. A number of critical implications on nuclear physics and astrophysics are discussed.