Fragmentation of single-particle strength and the validity of the shell model

Brand, M.G.E.; Rijsdijk, G.A.; Muller, F.; Allaart, K.; Dickhoff, W. H.

doi:10.1016/0375-9474(91)90612-a

Cited by 40 publications

(29 citation statements)

References 31 publications

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“…[188,189]. The study of the spectral strength distribution starting from a realistic NN interaction is only possible when shortrange correlations are properly included.…”

Section: Early Results For the Spectral Distributionmentioning

confidence: 99%

“…For this reason it has only recently been possible to obtain reliable experimental data in this correlated region which are still being analyzed [186,187]. Several studies have been carried out to obtain nuclear spectral functions at small and medium missing energies, mostly by computing the many-body Green's function [145], [188] - [196]. The qualitative features of the strength distribution at small and medium missing energies can be understood by realizing that a considerable mixing occurs between hole states and 2h1p configurations.…”

Section: Theoretical Calculations For Finite Nucleimentioning

confidence: 99%

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Self-consistent Green's function method for nuclei and nuclear matter

Dickhoff

Barbieri

2004

Progress in Particle and Nuclear Physics

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494

599

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Recent results obtained by applying the method of self-consistent Green's functions to nuclei and nuclear matter are reviewed. Particular attention is given to the description of experimental data obtained from the (e,e ′ p) and (e,e ′ 2N) reactions that determine one and two-nucleon removal probabilities in nuclei since the corresponding amplitudes are directly related to the imaginary parts of the single-particle and two-particle propagators. For this reason and the fact that these amplitudes can now be calculated with the inclusion of all the relevant physical processes, it is useful to explore the efficacy of the method of self-consistent Green's functions in describing these experimental data. Results for both finite nuclei and nuclear matter are discussed with particular emphasis on clarifying the role of short-range correlations in determining various experimental quantities. The important role of long-range correlations in determining the structure of lowenergy correlations is also documented. For a complete understanding of nuclear phenomena it is therefore essential to include both types of physical correlations. We demonstrate that recent experimental results for these reactions combined with the reported theoretical calculations yield a very clear understanding of the properties of all protons in the nucleus. We propose that this knowledge of the properties of constituent fermions in a correlated many-body system is a unique feature of nuclear physics.

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“…[188,189]. The study of the spectral strength distribution starting from a realistic NN interaction is only possible when shortrange correlations are properly included.…”

Section: Early Results For the Spectral Distributionmentioning

confidence: 99%

Section: Theoretical Calculations For Finite Nucleimentioning

confidence: 99%

Self-consistent Green's function method for nuclei and nuclear matter

Dickhoff

Barbieri

2004

Progress in Particle and Nuclear Physics

Self Cite

494

599

View full text Add to dashboard Cite

show abstract

“…The results of Refs. [42][43][44][45][46], suggest that this is large enough to properly account for the relevant low-energy collective states. The effective interaction (G matrix) was derived from the Bonn-C model of the NN potential V [47].…”

Section: A Two-nucleon Overlap Inside the Space Pmentioning

confidence: 99%

Effects of nuclear correlations on theO16(e,e′pN)reactions t

et al. 2004

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Calculations of the 16 O͑e , eЈp N͒ cross sections to the ground state and first excited levels of the 14 C and 14 N nuclei are presented. The effects of nuclear fragmentation have been obtained in a self-consistent approach and are accounted for in the determination of the two-nucleon removal amplitudes. The Hilbert space is partitioned in order to compute the contribution of both long-and short-range effects in a separate way. Both the twoproton and the proton-neutron emission cross sections have been computed within the same model for the nuclear structure as well as the same treatment of the reaction mechanism, with the aim of better comparing the differences between the two physical processes. The 16 O͑e , eЈ pp͒ reaction is found to be sensitive to shortrange correlations, in agreement with previous results. The 16 O͑e , eЈ pn͒ cross section to 1 + final states is dominated by the ⌬ current and tensor correlations. For both reactions, the interplay between collective (long-range) effects and short-range and tensor correlations plays an important role. This suggests that the selectivity of ͑e , eЈpN͒ reactions to the final state can be used to probe correlations also beyond short-range effects.

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“…There will be physical spreading, or fragmentation, of the strengths of the final states about their estimated energies (from the Hartree-Fock plus two-neutron residual interaction) [21]. We take this into account in the present calculations by the introduction of a parameterised spreading width, Γ(E), for each state, dependent on its excitation energy above the Fermi energy of the residual nucleus E F .…”

Section: Final-state Energy Spreadingmentioning

confidence: 99%

“…However, it was found that this match does not improve through the use of either a different Skyrme potential in the Hartree-Fock level energy calculations or a more sophisticated shell model calculation. Rather the differences in the number of levels present and/or their energies may be due to fragmentation [21] and hence accounted for in a general sense via our energy spreading prescription described previously. The angular distribution of tritons emitted due to the population of a specfic state will be related to its J π value.…”

Section: Spin Distributionmentioning

confidence: 99%

Calculations of Compound Nucleus Spin-Parity Distributions Populated via the (p,t) Reaction in Support of Surrogate Neutron Capture Measurements

Benstead¹,

Tostevin²,

Escher³

et al. 2016

EPJ Web of Conferences

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Abstract. The surrogate reaction method may be used to determine the cross section for neutron induced reactions not accessible through standard experimental techniques. This is achieved by creating the same compound nucleus as would be expected in the desired reaction, but through a different incident channel, generally a direct transfer reaction. So far, the surrogate technique has been applied with reasonable success to determine the fission cross section for a number of actinides, but has been less successful when applied to other reactions, e.g. neutron capture, due to a 'spin-parity mismatch'. This mismatch, between the spin and parity distributions of the excited levels of the compound nucleus populated in the desired and surrogate channels, leads to differing decay probabilities and hence reduces the validity of using the surrogate method to infer the cross section in the desired channel. A greater theoretical understanding of the expected distribution of levels excited in both the desired and surrogate channels is therefore required in order to attempt to address this mismatch and allow the method to be utilised with greater confidence. Two neutron transfer reactions, e.g. (p,t), which allow the technique to be utilised for isotopes further removed from the line of stability, are the subject of this study. Results are presented for the calculated distribution of compound nucleus states populated in 90 Zr, via the 92 Zr(p,t) 90 Zr reaction, and are compared against measured data at an incident proton energy of 28.56 MeV.

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Fragmentation of single-particle strength and the validity of the shell model

Cited by 40 publications

References 31 publications

Self-consistent Green's function method for nuclei and nuclear matter

Self-consistent Green's function method for nuclei and nuclear matter

Effects of nuclear correlations on theO16(e,e′pN)reactions t

Calculations of Compound Nucleus Spin-Parity Distributions Populated via the (p,t) Reaction in Support of Surrogate Neutron Capture Measurements

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