Constraints on Nuclear Symmetry Energy Parameters

A review is made of constraints on the nuclear symmetry energy parameters arising from binding measurements, theoretical chiral effective field predictions neutron matter properties, unitary gas conjecture, and measurements skin thicknesses dipole polarizabilities. While most studies have been confined to SV L, important roles played by, Ksym, or, equivalently, incompressibility KN, are discussed. Strong correlations among SV,L, KN found both energies theory. However, these somewhat differ in two cases, those theory smaller uncertainties. To 68% confidence, it that SV=32.0±1.1 MeV, L=51.9±7.9 MeV KN=152.2±38.1 MeV. Theoretical for thickness polarizability neutron-rich nuclei 48Ca, 120Sn, 208Pb compared recent experimental notably CREX PREX experiments Jefferson Laboratory. By themselves, I+II measurement 48Ca suggest L=121±47 L=?5±40 respectively, confidence. we show interactions optimally satisfying imply L=53±13 nearly range suggested by either mass or theory, also consistent with measurements. This small parameter implies R1.4=11.6±1.0 km ?1.4=228?90+148, which NICER X-ray LIGO/Virgo gravitational wave observations stars.