Data-driven uncertainty-quantified dispersive optical-model potentials*

Nuclear optical-model potentials, which characterize the interaction between two nuclei in a compact form, are an essential input for nuclear reaction calculations required in nuclear physics, astrophysics, cosmology, and engineering applications. Proper uncertainty quantification of the optical model is necessary to obtain reliable uncertainties on any result using the potential as an ingredient [1]. A physically consistent optical potential is also expected to be dispersive [2, 3]. Even though this property is often neglected, due to the associated significant increase in computational complexity, it allows for an unified description of scattering and structure properties, and it is very useful in constraining a phenomenological optical model, especially in regions of the nuclear chart where little or no experimental data are available.

In this work, we combine these two features, aiming to extend the approach discussed in ref. [1] to train an uncertainty-quantified dispersive optical potential with accuracy and sensitivity beyond the state of the art. I will discuss a first application focused on the calcium chain of isotopes, and the challenges and perspectives of the project.

[1]  C. D. Pruitt, J. E. Escher, and R. Rahman. “Uncertainty-quantified phenomenological optical potentials for single-nucleon scattering.” In: Phys. Rev. C 107.1 (Jan. 2023), p. 014602. doi: 10.1103/PhysRevC. 107.014602.

[2]  J. S. Toll. “Causality and the Dispersion Relation: Logical Foundations.” In: Phys. Rev. 104.6 (Dec. 1956), pp. 1760–1770. doi: 10.1103/PhysRev.104.1760.

[3]  M. C. Atkinson. “Developing nucleon self-energies to generate the ingredients for the description of nuclear reactions.” PhD thesis. Washington University in St. Louis, 2019. doi: 10.7936/2n1j-5949.