On the separability of microscopic optical model potentials and emerging bell-shape Perey-Buck nonlocality

Abstract

After nearly sixty years since its introduction, the phenomenological bell-shape Perey-Buck spatial nonlocality in the optical model potential for nucleon-nucleus scattering has remained unaccounted for from a microscopic standpoint. In this article we provide a quantitative account for such nonlocality considering fully nonlocal optical potentials in momentum space. The framework is based on a momentum-space in-medium folding model, where infinite nuclear matter $g$ matrices in Brueckner-Hartree-Fock approximation are folded to the target one-body mixed density. The study is based on chiral next-to-next-to-next-to-leading order (N3LO) as well as Argonne $v_{18}$ nucleon-nucleon bare interaction models. Applications focus on ${}^{40}$Ca($p,p$) scattering at beam energies in the range 11-200 MeV, resulting in the identification of a separable structure of the momentum-space optical potential of a form we coin as $JvH$, with a nonlocality form factor as one of its terms. The resulting nonlocaliy form factor features a bell-shape with nonlocality range $\beta$ between 0.86 and 0.89 fm, for both proton and neutron beams at energies below 65 MeV. An analytic toy model is introduced to elucidate the underlying mechanism for the nonlocality in the optical model, providing an estimate of its range based on the Fermi motion of the target nucleons and the long-range part of the $NN$ interaction.

arXiv comment11 pages, 10 figures, 2 tables. Minor corrections. Accepted for publication in The European Physical Journal A (EPJA)

References in corpus (17)

• An accurate nucleon-nucleon potential with charge-independence breaking
• Accurate Charge-Dependent Nucleon-Nucleon Potential at Fourth Order of Chiral Perturbation Theory
• Forging the link between nuclear reactions and nuclear structure
• Microscopic self-energy calculations and dispersive optical-model potentials
• Nonlocal extension of the dispersive-optical-model to describe data below the Fermi energy
• Non-localities in nucleon-nucleus potentials
• Extension of the full-folding optical model for nucleon-nucleus scattering with applications up to 1.5 GeV
• Di-neutrons in neutron matter within Brueckner-Hartree-Fock approach
• Ab initio Translationally Invariant Nonlocal One-body Densities from No-core Shell-model Theory
• Energy dependence of non-local potentials
• SWANLOP : Scattering waves off nonlocal optical potentials in the presence of Coulomb interactions
• Low-density homogeneous symmetric nuclear matter: disclosing dinucleons in coexisting phases
• Nonlocal nucleon-nucleus interactions in (d,p) reactions: Role of the deuteron D-state
• Effects of nonlocality of nuclear potentials on direct capture reactions
• Surface-peaked medium effects in the interaction of nucleons with finite nuclei
• Di-nucleon structures in homogeneous nuclear matter based on two- and three-nucleon interactions
• Functional medium-dependence of the nonrelativistic optical model potential

Cited by in corpus (1)

• Chiral uncertainties in ab initio nucleon-nucleus elastic scattering