A program for calculating spectroscopic amplitudes for two-nucleon transfer reactions by projecting angular momentum

Takemasa, T.

doi:10.1016/0010-4655(85)90019-0

Cited by 4 publications

(9 citation statements)

References 4 publications

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“…An estimate [21,22] of O|P * vs. 2 in the range of interest, shown in Fig. 2, justifies the assumption above.…”

Section: The Two-level Modelsupporting

confidence: 78%

Structure of $^{43}$P and $^{42}$Si in a two-level shape-coexistence model

Macchiavelli,

Crawford,

Campbell

et al. 2021

Preprint

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Exclusive cross sections for the 43 P(−1p) 42 Si reaction to the lowest 0 + and 2 + states, measured at NSCL with GRETINA and the S800, are interpreted in terms of a two-level mixing (collective) model of oblate and prolate co-existing shapes. Using the formalism developed for deformed nuclei we calculate the spectroscopic amplitudes and exclusive cross-sections in the strong coupling limit, where for 43 P the schematic wavefunction includes the coupling of the Nilsson [211] 1 2 proton orbit. Good agreement with the experimental data is obtained when the amplitude of the oblate configuration is 80%, suggesting that both nuclei are predominantly oblate, in line with theoretical expectations.

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“…An estimate [21,22] of O|P * vs. 2 in the range of interest, shown in Fig. 2, justifies the assumption above.…”

Section: The Two-level Modelsupporting

confidence: 78%

Structure of $^{43}$P and $^{42}$Si in a two-level shape-coexistence model

Macchiavelli,

Crawford,

Campbell

et al. 2021

Preprint

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“…The 1/2 + 1 must have anti-parallel coupling of j with the core rotation, R. It follows that in the decoupled limit ( 2 → 0) the energy of the 1/2 + 1 state with respect to the ground state is proportional to the rotational energy of the core, E 2 + (core). Together with the 9/2 + 1 state they provide a proxy for the 2 + energy of the effective 24 O core in 25 F. Adjusting to the energies of the 1/2 + 1 and 9/2 + 1 states gives E 2 + (core) ≈ 3.2 MeV, in line with a modest quadruple deformation, 2 ≈ 0.15, and consistent with the conditions required for the appearance of a decoupled band.…”

Section: A Level Energiessupporting

confidence: 60%

“…In a recent work [7], the structure of 25 F has been investigated via (p, 2p) quasi-free knockout experiments with exclusive measurements using a 25 F beam at RIBF/RIKEN. The analysis of measured cross-sections and derived spectroscopic factors may imply that the core of 25 F consists of ∼ 35% 24 O gs and ∼ 65% excited 24 O. As discussed by the authors, their results suggest that the addition of the 0d 5/2 proton considerably changes the neutron structure in 25 F from that in 24 O, and calls for a revision to the np tensor interaction in the widely used effective interactions, which appears to be too weak to reproduce the observations.…”

Section: Introductionmentioning

confidence: 99%

“…The analysis of measured cross-sections and derived spectroscopic factors may imply that the core of 25 F consists of ∼ 35% 24 O gs and ∼ 65% excited 24 O. As discussed by the authors, their results suggest that the addition of the 0d 5/2 proton considerably changes the neutron structure in 25 F from that in 24 O, and calls for a revision to the np tensor interaction in the widely used effective interactions, which appears to be too weak to reproduce the observations. In contrast, studies of neutron decay from unbound excited states in 24 In this article we follow up on our earlier work [11] and interpret the above results in terms of a collective picture, within the framework of the Particle-Rotor Model (PRM) [12,13] to provide further insight into the nature of the effective 24 O core in 25 F.…”

Section: Introductionmentioning

confidence: 99%

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Core of F25 in the rotational model

et al. 2020

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In a recent experiment, carried out at RIBF/RIKEN, the 25 F(p, 2p) 24 O reaction was studied at 270 MeV/A in inverse kinematics. Derived spectroscopic factors suggest that the effective core of 25 F significantly differs from a free 24 O nucleus. We interpret these results within the Particle-Rotor Model and show that the experimental level scheme of 25 F can be understood in the rotation-aligned coupling scheme, with its 5/2 + 1 ground state as the band-head of a decoupled band. The excitation energies of the observed 1/2 + 1 and 9/2 + 1 states correlate strongly with the rotational energy of the effective core, seen by the odd proton, and allow us to estimate its 2 + energy at ≈ 3.2 MeV and a moderate quadrupole deformation, 2 ≈ 0.15. The measured fragmentation of the πd 5/2 singleparticle strength is discussed and some further experiments suggested.

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“…where the T XY are the TNAs derived from the overlaps, A; Y|A + 2; X , of each initial (X) and final (Y) shape configuration, being either S, O, or P. These individual TNAs, T XY , involving initial and final configurations with different deformation, are calculated within the Nilsson and BCS framework using the methodology of Takemasa [30]. The wave functions are constructed by projection of the Nilsson and BCS wave functions onto a definite angular momentum state.…”

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confidence: 99%

Shell and shape evolution atN=28: TheMg40ground state

Crawford¹,

Fallon²,

Macchiavelli³

et al. 2014

Phys. Rev. C

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A measurement of the direct two-proton removal from 42 Si has provided the first structural information on the N = 28 isotone 40 Mg. The value for the inclusive cross section for two-proton removal from 42 Si of 40 +27 −17 μb is significantly lower than that predicted by structure calculations using the recent SDPF-MU shell-model effective interaction combined with eikonal reaction theory. This observed discrepancy is consistent with the interpretation that only one of the predicted low-lying 0 + states in 40 Mg is bound. A two-state mixing analysis describing two-proton knockout cross sections along N = 28 provides support for the interpretation of a prolate-deformed 40 The study of nuclei far from the line of β stability is one of the most active and challenging areas of current nuclear structure physics. Exotic combinations of protons (Z) and neutrons (N ) can significantly affect the underlying shell structure, and for weakly bound nuclei at or near the dripline, the proximity to continuum states may further alter nuclear properties. Benchmarking and constraining theory at the very limits of existence is critical, and one of the most exotic neutron-rich nuclei currently accessible to experiment is 40 Mg.First observed following fragmentation of a 48 Ca primary beam at the National Superconducting Cyclotron Laboratory in 2007 (with three events) [1], 40 12 Mg 28 lies at an intersection for nucleon magic numbers and the neutron dripline. It is expected to exhibit [2] the collective and deformed properties characteristic of the N = 28 isotones below 48 Ca, which is a region of rapidly changing nuclear shapes. Large-scale shell-model calculations predict that 40 Mg should be a welldeformed prolate rotor [3]. In addition, the last bound neutron orbital is expected to be the low-l p 3/2 state, leading to the possibility that weak binding effects could play a role.Further, deformation along the Z = 12 isotopic chain has been of recent experimental interest, with the work of Doornenbal et al. [4], in which an extended region of deformation in the Mg isotopes from the quenched N = 20 gap out to N = 26 is observed, as determined by the ratio of E(4 + 1 )/E(2 + 1 ), and is expected to persist at N = 28. We present here the first experimental structure information on 40 Mg following measurement of the inclusive two-proton removal cross section from 42 Si and discuss the results as a part of the overall shape evolution along the N = 28 isotonic chain. We provide a limit on the number of bound states predicted by theory, and evidence supporting a prolate-deformed 40 Mg ground state based on a two-state mixing model.One-and two-proton knockout reactions from 42 Si were carried out at Radioactive Isotope Beam Factory (RIBF), operated by RIKEN Nishina Center and the Center for Nuclear Study, University of Tokyo. A primary beam of 48 Ca, at an energy of 345 MeV/nucleon, with an average intensity of approximately 70 pnA, was fragmented in a thick (15-mm) rotating Be production target to produce a cocktail of projectile...

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A program for calculating spectroscopic amplitudes for two-nucleon transfer reactions by projecting angular momentum

Cited by 4 publications

References 4 publications

Structure of $^{43}$P and $^{42}$Si in a two-level shape-coexistence model

Structure of $^{43}$P and $^{42}$Si in a two-level shape-coexistence model

Core of F25 in the rotational model

Shell and shape evolution atN=28: TheMg40ground state

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