Validity of the distorted-wave impulse-approximation description of Ca 40 (e,e′p) K 39 data using only ingredients from a nonlocal dispersive optical model

M. C. Atkinson*, H. P. Blok, L. Lapikás, R. J. Charity, W. H. Dickhoff

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


The nonlocal implementation of the dispersive optical model (DOM) provides all the ingredients for distorted-wave impulse-approximation (DWIA) calculations of the (e,e′p) reaction. It provides both the overlap function, including its normalization, and the outgoing proton distorted wave. This framework is applied to describe the knockout of a proton from the 0d32 and 1s12 orbitals in Ca40 with fixed normalizations of 0.71 and 0.60, respectively. Data were obtained in parallel kinematics for three outgoing proton energies: 70, 100, and 135 MeV. Agreement with the data is as good as, or better than, previous descriptions employing local optical potentials and overlap functions from Woods-Saxon potentials - both with standard nonlocality corrections - whose normalization (spectroscopic factor) and radius were fitted to the data. The present analysis suggests that slightly larger spectroscopic factors are obtained when nonlocal optical potentials are employed than those generated with local potentials. The results further suggest that the chosen kinematical window around 100 MeV proton energy provides the best and cleanest method to employ the DWIA for the analysis of this reaction. The conclusion that substantial ground-state correlations cannot be ignored when describing a closed-shell atomic nucleus is therefore confirmed in detail. To reach these conclusions, it is essential to have a complete description of the nucleon single-particle propagator that accounts for all elastic nucleon-scattering observables in a wide energy domain up to 200 MeV. The current nonlocal implementation of the DOM fulfills this requirement.

Original languageEnglish
Article number044627
Pages (from-to)1-14
Number of pages14
JournalPhysical Review C
Issue number4
Publication statusPublished - 31 Oct 2018


The authors thank Carlotta Giusti for providing us with a recent version of the DWEEPY code. This work was supported by the U.S. Department of Energy, Division of Nuclear Physics, under Grant No. DE-FG02-87ER-40316; by the U.S. National Science Foundation under Grant No. PHY-1613362, and the Dutch Foundation for Fundamenteel Onderzoek der Materie (FOM), which was financed by the Netherlands Organisation for Scientific Research (NWO).

FundersFunder number
Division of Nuclear PhysicsDE-FG02-87ER-40316
Dutch Foundation for Fundamenteel Onderzoek der Materie
National Science FoundationPHY-1613362
U.S. Department of Energy
Stichting voor Fundamenteel Onderzoek der Materie
Nederlandse Organisatie voor Wetenschappelijk Onderzoek


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