ICCUB Seminar

Nuclear Symmetry Energy and the Breaking of the Isospin Symmetry: How Do They Reconcile with Each Other?

By Xavier Roca-Maza (Università degli Studi di Milano & INFN Milano)   

Thursday 14 Jan , 11:00:00


Density Functional Theory (DFT) and the so called ab initio methods constitute two different and complementary approaches to the nuclear many-body problem. While the latter encounter computational limitations, the former is currently the only available method that can be applied to the whole nuclear chart. DFT allows the study of both ground state properties and nuclear excitations, and finds successful applications in nuclear structure and nuclear astrophysics.

I will briefly introduce the strong synergy between “heaven and earth” which is instrumental in the study of the nuclear Equation of State (EoS). That is, the relevance of ground experiments as well as accurate astronomical observations on neutron stars and gravitational waves to shed light into one of the most challenging problems of our times: how does subatomic matter organize itself.

On the basis of DFT, I will present our recent proposed solution to the apparent inconsistency between our current knowledge of the EoS, the energy of the isobaric analog state (IAS) in a heavy nucleus such as 208Pb (see a simple example in the figure for 90Zr), and the isospin symmetry breaking forces in the nuclear medium [1].

This is achieved by performing state-of-the-art IAS calculations that include all isospin symmetry breaking contributions. To this aim, we propose a new energy density functional that is successful in reproducing the IAS excitation energy without compromising other properties of finite nuclei. Applications to the mass radius relation of a cold non-accreting neutron star will be briefly discussed.

Future perspectives on the efforts of building more accurate nuclear energy density functionals will be also given.