Dispersive-optical-model analysis of the asymmetry dependence of correlations in Ca isotopes

Charity, R. J.; Mueller, J.M.; Sobotka, L. G.; Dickhoff, W. H.

doi:10.1103/physrevc.76.044314

Cited by 70 publications

(147 citation statements)

References 86 publications

(134 reference statements)

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“…For example, 3N forces raise the radius of 44 Ca to 2.94 fm (closer to the experimental value of 3.52 fm) and the neutron f 7/2 -d 3/2 shell gap is reduced to 7.2 MeV, in agreement with the data-driven predictions of Ref. [38]. Figure 3 displays one-neutron addition and removal spectral strength distributions (SSDs) in 44 Ca.…”

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confidence: 72%

Ab initioGorkov-Green's function calculations of open-shell nuclei

2013

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We present results from a new ab initio method that uses the self-consistent Gorkov-Green's function theory to address truly open-shell systems. The formalism has been recently worked out up to second order and is implemented here in nuclei on the basis of realistic nuclear forces. Benchmark calculations indicate that the method is in agreement with other ab initio approaches in doubly closed shell 40 Ca and 48 Ca. We find good convergence of the results with respect to the basis size in 44 Ca and 74 Ni and discuss quantities of experimental interest including ground-state energies, pairing gaps, and particle addition and removal spectroscopy. These results demonstrate that the Gorkov method is a valid alternative to multireference approaches for tackling degenerate or near-degenerate quantum systems. In particular, it increases the number of mid-mass nuclei accessible in an ab initio fashion from a few tens to a few hundred.

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confidence: 72%

Ab initioGorkov-Green's function calculations of open-shell nuclei

2013

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“…The present approach is complementary to the highly developed folding model, e.g., [12][13][14][15], incorporating a local density, LD, model. As remarked by Köhler [30] in the context of core polarization in shell model calculations, particle-hole excitations are allowed in finite systems.…”

Section: Discussionmentioning

confidence: 99%

“…Fitting data like that mentioned above evidently requires physics beyond the highly developed [12][13][14][15] local density model. Such models would not seem to have any place for angular momentum dependence, for example.…”

Section: Introductionmentioning

confidence: 99%

Phonon coupling effects in proton scattering fromCa40

Mackintosh

Keeley

2014

Phys. Rev. C

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Background: Formal optical model theory shows that coupling to vibrational nuclear states generates a nonlocal and l-dependent dynamical polarization potential (DPP). Little is established concerning the DPP, yet its properties are crucial for explaining the departures of optical model potentials (OMPs) from global behavior and for the rigorous extraction of spectroscopic information from direct reactions. Purpose: To appraise the application of channel coupling followed by S-matrix inversion for the systematic exploration of the contribution of the coupling of collective states to the nucleon OMP and to identify properties of nuclear potentials indicative of l-dependence. Methods: S-matrix to potential, S lj → V (r) + l · s V SO (r), inversion provides local potentials that precisely reproduce the elastic channel S-matrix from coupled channel (CC) calculations. Subtracting the elastic channel uncoupled (bare) potential yields a local and l-independent representation of the DPP. The dependence of this local DPP upon the nature of the coupled states and upon other parameters can be studied. Results: All components of the DPP arising from coupling to vibrational states are substantially undulatory with a point-by-point magnitude therefore disproportionate to their contribution to volume integrals. Information relating to dynamical nonlocality is found. The proton charge leads to a substantial difference between DPPs for protons and neutrons. Conclusions: Undulatory features in potentials found in precision fits to elastic scattering data are significant, are a consequence of coupling to inelastic channels and must be allowed for in phenomenology; they are indirect evidence of l-dependence. Within the model, coupling to excited states magnifies the effect of the proton charge on the difference between proton-nucleus and neutron-nucleus interactions. Coupled channel plus inversion is a procedure of wide applicability, complementary to evaluation of the Feshbach formalism.

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“…In particular we refer to previous papers for a description of ingredients that have not changed from the purely local treatment of the DOM [14,15]. The nonlocal treatment of the HF potential was discussed in Ref.…”

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confidence: 99%

“…[15] whereas for surface absorption we employed the form of Ref. [14]. The solution of the Dyson equation below the Fermi energy was introduced in Ref.…”

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confidence: 99%

Forging the Link between Nuclear Reactions and Nuclear Structure

et al. 2014

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A comprehensive description of all single-particle properties associated with the nucleus 40 Ca is generated by employing a nonlocal dispersive optical potential capable of simultaneously reproducing all relevant data above and below the Fermi energy. The introduction of nonlocality in the absorptive potentials yields equivalent elastic differential cross sections as compared to local versions but changes the absorption profile as a function of angular momentum suggesting important consequences for the analysis of nuclear reactions. Below the Fermi energy, nonlocality is essential to allow for an accurate representation of particle number and the nuclear charge density. Spectral properties implied by (e, e ′ p) and (p, 2p) reactions are correctly incorporated, including the energy distribution of about 10% high-momentum nucleons, as experimentally determined by data from Jefferson Lab. These high-momentum nucleons provide a substantial contribution to the energy of the ground state, indicating a residual attractive contribution from higher-body interactions for 40 Ca of about 0.64 MeV/A.PACS numbers: 21.10. Pc,24.10.Ht,11.55.Fv The properties of a nucleon that is strongly influenced by the presence of other nucleons have traditionally been studied in separate energy domains. Positive energy nucleons are described by fitted optical potentials mostly in local form [1,2]. Bound nucleons have been analyzed in static potentials that lead to an independent-particle model modified by the interaction between valence nucleons as in traditional shell-model calculations [3,4]. The link between nuclear reactions and nuclear structure is provided by considering these potentials as representing different energy domains of one underlying nucleon self-energy. This idea was implemented in the dispersive optical model (DOM) by Mahaux and Sartor [5]. By employing dispersion relations, the method provides a critical link between the physics above and below the Fermi energy with both sides being influenced by the absorptive potentials on the other side.The DOM provides an ideal strategy to predict properties for exotic nuclei by utilizing extrapolations of these potentials towards the respective drip lines [6,7]. The main stumbling block so far has been the need to utilize the approximate expressions for the properties of nucleons below the Fermi energy that were developed by Mahaux and Sartor [5] to correct for the normalizationdistorting energy dependence of the Hartree-Fock (HF) potential. By restoring the proper treatment of nonlocality in the HF contribution, it was possible to overcome this problem [8] although the local treatment of the absorptive potentials yielded a poor description of the nuclear charge density and particle number.In the present work we have for the first time treated the nonlocality of these potentials for the nucleus 40 Ca with the aim to include all available data below the Fermi energy that can be linked to the nucleon single-particle propagator [9] while maintaining a correct description of the el...

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Dispersive-optical-model analysis of the asymmetry dependence of correlations in Ca isotopes

Cited by 70 publications

References 86 publications

Ab initioGorkov-Green's function calculations of open-shell nuclei

Ab initioGorkov-Green's function calculations of open-shell nuclei

Phonon coupling effects in proton scattering fromCa40

Forging the Link between Nuclear Reactions and Nuclear Structure

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