Beyond Woods–Saxon: Microscopic Perspectives on Optical Potentials

par Guillaume Blanchon (CEA DAM)

mercredi 1 oct. 2025, 11:00 → 12:00 Europe/Paris

100/2-A201 - Salle A201 (IJCLab)

Optical potentials are used to describe nucleon–nucleus scattering, yet traditional phenomenological forms—such as Woods–Saxon or Perey–Buck—remain limited in how they incorporate nonlocality and dispersive effects. In this talk, I will introduce the basic ideas behind nonlocal and dispersive optical potentials, emphasizing their role in linking nuclear reactions to nuclear structure, and review recent advances toward phenomenological models guided by microscopic theory. I will also present some of the numerical tools developed to solve the corresponding integro-differential scattering equation.

Building on a momentum-space in-medium folding model, I will then discuss a systematic study of the universal separability of the optical potential over a broad range of energies (40–400 MeV) and target masses (40 ≤ A ≤ 208). This analysis shows that thenonlocality form factor is inherently complex and hydrogenic in nature, affecting both central and spin–orbit components. A striking result is the consistent appearance of a nodal point in the imaginary radial form factor, which suppresses surface absorption—contradicting the Woods–Saxon picture of maximal absorption at the nuclear surface. Finally, I will show how the complex radial dependence can be expressed in terms of simple building blocks, namely the convolution of a uniform spherical distribution with a Gaussian and a Yukawa term, thus offering a new framework for constructing realistic optical potentials.

 

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How to reach the seminar room:

Whereabouts of the laboratory on the Paris-Saclay campus

Bat. 100, general room map