Constraints on the skewness coefficient of symmetric nuclear matter within the nonlinear relativistic mean field model

Within the nonlinear relativistic mean field(NLRMF) model, we show that both the pressure of symmetric nuclear matter at supra-saturation densities and the maximum mass of neutron stars are sensitive to the skewness coefficient, J_0, of symmetric nuclear matter. Using experimental constraints on the pressure of symmetric nuclear matter at supra-saturation densities from flow data in heavy-ion collisions and the astrophysical observation of a large mass neutron star PSR J0348+0432, with the former favoring a smaller J_0 while the latter favors a larger J_0, we extract a constraint of -494 MeV≤J_0≤-10 MeV based on the NL-RMF model. This constraint is compared with the results obtained in other analyses.

How tightly is the nuclear symmetry energy constrained by a unitary Fermi gas?

We examine critically how tightly the density dependence of nuclear symmetry energy E_(sym)(q) is constrained by the universal equation of state of the unitary Fermi gas EUG(q) considering currently known uncertainties of higher order parameters describing the density dependence of the equation of state of isospin asymmetric nuclear matter. We found that E_(UG)(q) does provide a useful lower boundary for the E_(sym)(q). However, it doesnot tightly constrain the correlation between the magnitude E_(sym)(q_0) and slope L unless the curvature K_(sym)of the symmetry energy at saturation density q_0 is more precisely known. The large uncertainty in the skewness parameters affects the E_(sym)(q_0) versus L correlation by the same almost as significantly as the uncertainty in K_(sym).

Isospin dependence of nucleon effective masses in neutron-rich matter

In this talk,we first briefly review the isospin dependence of the total nucleon effective mass M Jinferred from analyzing nucleon-nucleus scattering data within an isospin-dependent non-relativistic optical potential model,and the isospin dependence of the nucleon E-mass M;E J obtained from applying the Migdal–Luttinger theorem to a phenomenological single-nucleon momentum distribution in nuclei constrained by recent electron-nucleus scatteringexperiments.Combining information about the isospin dependence of both the nucleon total effective mass and E-mass,we then infer the isospin dependence of nucleon k-mass using the well-known relation M_J~*=M_ J^(*1E).Implications of the results on the nucleon mean free path in neutron-rich matter are discussed.