Isospin dependence of incompressibility in relativistic and nonrelativistic mean field calculations

The isospin dependence of incompressibility is investigated in Skyrme Hartree-Fock (SHF) and relativistic mean field (RMF) models. The correlations between the nuclear matter incompressibility and the isospin-dependent term of the finite nucleus incompressibility is elucidated using the Thomas-Fermi approximation. The Coulomb term is also studied by using various different Skyrme Hamiltonians and RMF Lagrangians. Microscopic HF+random phase approximation (RPA) calculations are performed with Skyrme interactions for Pb-208 and Sn isotopes to study the strength distributions of isoscalar giant monopole resonances. The symmetry term of nuclear incompressibility is extracted to be K-tau=-(500 +/- 50) MeV from the recent experimental data of isoscalar giant monopole resonances (ISGMR) in Sn isotopes.