PI: Matteo Vorabbi
The description of the scattering process between a projectile nucleon and a target nucleus represents a valuable tool to extract information about the nuclear properties of the system that is under consideration. The understanding of these properties is ultimately related to the understanding of the limits of nuclear stability, which is one of the fundamental questions in nuclear physics. There is a huge experimental effort devoted on studying the properties of these systems located away from the stability line and focused on establishing the boundary beyond which a nucleus is not bound anymore. However, these experiments are not free from sizeable uncertainties and require reliable theoretical approaches to support the analysis of the experimental data and drive future experiments. In this context is extremely important to develop microscopic approaches based on the underlying inter-nucleon dynamics and completely free from phenomenology, to ensure a higher predictive power. One fundamental tool that has been widely adopted to describe nuclear reactions is the optical potential. The idea behind this approach is to provide an effective potential that describes how the incoming projectile interacts with the target nucleus.
With the progress made in theoretical nuclear physics, it is now possible to calculate this potential microscopically combining nuclear scattering theory and ab initio methods. A promising and reliable approach is provided by the Self-Consistent Green’s Function (SCGF), that offers a natural way to compute the necessary many-body ingredients required for the microscopic calculation of the optical potential over a wide area of the nuclear chart. In Ref. [1] we performed the first calculation of a microscopic optical potential for medium-mass nuclei, focussing on the calcium and nickel isotopic chains. The optical potential is obtained folding the free two-nucleon scattering matrix and the nuclear density obtained from the SCGF calculation. Where possible, we compared our theoretical results with existing experimental data to test the quality of our potential. The figure shows an example of differential cross sections for elastic proton scattering off 40Ca for different energies of the incoming proton. In general, our calculations give a good description of the experimental data for scattering angles up to about 60 degrees and a reasonable description at larger angles. Future developments involve the inclusion of medium effects to further improve the description of the data.
[1] M. Vorabbi, C. Barbieri, V. Somà, P. Finelli, and C. Giusti, Phys. Rev. C 109, (2024) 034613.