Giant resonances in 40Ca and 48Ca, M. R. Anders, S. Shlomo, Cyclotron Institute, Texas A&M University, College Station, Texas 77840 − The study of collective modes in nuclei has been the subject of extensive theoretical and experimental studies during several decades, since it contributes significantly to our understanding of bulk properties of nuclei, their non-equilibrium properties and properties of the nuclear force. Of particular interest is the equation of state (EOS), i.e. the binding energy per nucleon as a function of matter density, of infinite nuclear matter (no Coulomb interaction). The EOS is an important ingredient in the study of properties of nuclei at and away from stability, structure and evolution of compact astrophysical objects, such as neutron stars and core-collapse supernovae, and of heavy-ion collisions. To extend our knowledge of the EOS beyond the saturation point of the symmetric NM (SNM), an accurate value of the NM incompressibility coefficient KNM, which is directly related to the curvature of the EOS, is needed. An accurate value of the density dependence of the symmetry energy coefficient, J, is needed for the EOS of asymmetric NM.

 

It is well known that the energies of the compression modes, the isoscalar giant monopole resonance (ISGMR) and isoscalar giant dipole resonance (ISGDR), are very sensitive to the value of KNM.  Also the energies of the isovector giant resonances, in particular, the isovector giant dipole resonance (IVGDR), are sensitive to the density dependence of J. Furthermore, information on the density dependence of J can also be obtained by studying the isotopic dependence of strength functions, such as the difference between the strength functions of 40Ca and 48Ca.

 

We will present results of fully self-consistent Hartree Fock based random phase approximation calculations of the strength functions and centroid energies ECEN of isoscalar (T = 0) and isovector (T = 1) giant resonances of multipolarities L = 0 - 3 in 40Ca and 48Ca, using a wide range of commonly employed Skyrme type nucleon-nucleon effective interactions. We will discuss the sensitivity of ECEN and of the differences ECEN(48Ca) - ECEN(40Ca) to physical quantities, such as nuclear mater incompressibility coefficient and symmetry energy, associated with the effective nucleon-nucleon interactions and compare the results with available experimental data.