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

Abstract

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