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Résumé |
The optical potential is a well-known and successful tool that is widely used to
describe nucleon-nucleus scattering processes. Within this approach it is
possible to compute the scattering observables for elastic processes across wide
regions of the nuclear landscape and extend its usage to inelastic scattering
and other types of reactions. A phenomenological approach is usually preferred
to achieve a good description of the data. However, it lacks predictive power
due to the presence of free parameters contained in the model that need to be
fixed. With the upcoming facilities for exotic nuclei, we strongly believe that
a microscopic approach, completely free from phenomenology, will be the
preferred tool to make reliable predictions, assess the unavoidable
approximations, and provide a clear physical interpretation of the process under
consideration. The Watson multiple scattering theory provides a successful
framework to derive such optical potential for energies above ~100 MeV. In its
simplest formulation, derived at the first order, the optical potential is
obtained as the folding integral of the nucleon-nucleon scattering t matrix and
the target density, representing the two fundamental ingredients of the model.
After many years of advances in theoretical nuclear physics, it is now possible
to calculate these two quantities using the same nucleon-nucleon interaction
that is the only input of our calculations. Results obtained within this
framework will be presented for light- and medium-mass nuclei, adopting
different ab initio approaches to calculate the densities, such as No-Core Shell
Model and Self-Consistent Green's Function. Preliminary results for future
extensions of the model, such as the inclusion of medium effects and the
calculation of the inelastic scattering, will be also presented. Finally, we
will also present the extension of the multiple scattering formalism to derive a
nucleus-nucleus optical potential for elastic scattering calculations.
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