Towards Ab-Initio Calculations of Electromagnetic Reactions in Medium-Mass Nuclei

Electromagnetic reactions with nuclei are important in many fields of physics ranging from nuclear physics to astrophysics. The response of a nucleus to the interaction of an external electromagnetic probe is a crucial observable to test our understanding of nuclear dynamics. Until very recently, most of the ab-initio calculations of such reactions where the nucleus is broken in several pieces, were restricted to very light nuclei ($A\le 7$). By merging coupled-cluster theory and the Lorentz integral transform method one can extend the ab-initio study of electromagnetic break-up reactions to the region of medium-mass nuclei . We first benchmark the new method in \textsuperscript{4}He and then address the photo-disintegration of \textsuperscript{16}O. We then move to \textsuperscript{40}Ca and \textsuperscript{48}Ca, and investigate the electric dipole polarizability. Preliminary results indicate a correlation between the polarizability and the neutron-skin radius of \textsuperscript{48}Ca. This latter is attracting a lot of attention in nuclear physics and experiments to measure both the polarizability and the neutron-skin radius are planned/ongoing at RCNP and JLAB respectively.