Structure of 
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 and the magicity of the 
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 gap at 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Z</mml:mi><mml:mo>=</mml:mo><mml:mn>14</mml:mn></mml:mrow></mml:m

Jongile, S.; Lemasson, A.; Sorlin, O.; Wiedeking, M.; Papka, P.; Bazin, D.; Borcea, C.; Borcea, R.; Gade, A.; Iwasaki, H.; Khan, E.; Lepailleur, A.; Mutschler, A.; Nowacki, F.; Recchia, F.; Roger, T.; Rotaru, F.; Stănoiu, M.; Stroberg, S. R.; Tostevin, J. A.; Vanderbrouck, M.; Weißhaar, D.; Wimmer, K.

doi:10.1103/physrevc.102.024321

Cited by 10 publications

(3 citation statements)

References 42 publications

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“…As presented in Table III, its high E x (2 + 1 ) [76] and E x (0 + 2 ) [73], combining the small B(E2; 0 + 1 → 2 + 1 ) [77], are direct indications of shell closure. Additionally, experimental data on neutron and proton occupation in 34 Si [78][79][80] and neutron single-particle structure in 35 Si [81] validated this interpretation. In some of the shell-model calculations, however, the 0p0h component is reduced to 60 % (SDPF-M) and even 20 % (EEdf1), showing less doubly-magic features.…”

Section: Configurations In the Shell-model Wave Functionsmentioning

confidence: 59%

In-beam $γ$-ray spectroscopy of $^{32}$Mg via direct reactions

Kitamura,

Wimmer,

Miyagi

et al. 2022

Preprint

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Background: The nucleus 32 Mg (N = 20 and Z = 12) plays a central role in the so-called "island of inversion" where in the ground states sd-shell neutrons are promoted to the f p-shell orbitals across the shell gap, resulting in the disappearance of the canonical neutron magic number N = 20.Purpose: The primary goals of this work are to extend the level scheme of 32 Mg, provide spin-parity assignments to excited states, and discuss the microscopic structure of each state through comparisons with theoretical calculations.Method: In-beam γ-ray spectroscopy of 32 Mg was performed using two direct-reaction probes, one-neutron (twoproton) knockout reactions on 33 Mg ( 34 Si). Final-state exclusive cross sections and parallel momentum distributions were extracted from the experimental data and compared with eikonal-based reaction model calculations combined with shell-model overlap functions.Results: Owing to the remarkable selectivity of the one-neutron and two-proton knockout reactions, a significantly updated level scheme for 32 Mg, which exhibits negative-parity intruder and positive-parity normal states, was constructed. The experimental results were confronted with four different nuclear structure models. Conclusions:In some of these models, different aspects of 32 Mg and the transition into the island of inversion are well described. However, unexplained discrepancies remain, and even with the help of these state-of-the-art theoretical approaches, the structure of this key nucleus is not yet fully captured.

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Section: Configurations In the Shell-model Wave Functionsmentioning

confidence: 59%

In-beam $γ$-ray spectroscopy of $^{32}$Mg via direct reactions

Kitamura,

Wimmer,

Miyagi

et al. 2022

Preprint

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“…Right: Excitation energies for the lowest-lying 3/2 − and 7/2 − states in N =19 isotones. Values taken from Refs [13,37,40,41]…”

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confidence: 99%

Border of the Island of Inversion: Unbound states in $^{29}$Ne

Holl,

Lindberg,

Heinz

et al. 2022

Preprint

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The nucleus 29 Ne is situated at the border of the island of inversion. Despite significant efforts, no bound low-lying intruder f 7/2 -state, which would place 29 Ne firmly inside the island of inversion, has yet been observed. Here, the first investigation of unbound states of 29 Ne is reported. The states were populated in 30 Ne(p, pn) and 30 Na(p, 2p) reactions at a beam energy of around 230 MeV/nucleon, and analyzed in terms of their resonance properties, partial cross sections and momentum distributions. The momentum distributions are compared to calculations using the eikonal, direct reaction model, allowing -assignments for the observed states. The lowest-lying resonance at an excitation energy of 1.48(4) MeV shows clear signs of a significant =3-component, giving first evidence for f 7/2 single particle strength in 29 Ne. The excitation energies and strengths of the observed states are compared to shell-model calculations using the sdpf-u-mix interaction.

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“…Here, we report on in-beam γ-ray spectroscopy of 32 Mg produced using two different direct reactions, 9 Be( 33 Mg, 32 Mg)X one-neutron and 9 Be( 34 Si, 32 Mg)X two-proton knockout, whose use as a spectroscopic tool has been established [25]. The advantage of this unique approach is that these two reactions are expected to have different selectivity for final states in 32 Mg, because 34 Si is considered to be of doublymagic nature [22,[26][27][28], whereas 33 Mg is itself located inside the island of inversion where particle-hole configurations dominate in the ground states [29]. In the present Letter, we discuss the main results of the experiment and implications for the understanding of the structure of nuclei in the island of inversion.…”

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confidence: 99%

Coexisting normal and intruder configurations in $^{32}$Mg

Kitamura,

Wimmer,

Poves

et al. 2021

Preprint

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Situated in the so-called "island of inversion," the nucleus 32 Mg is considered as an archetypal example of the disappearance of magicity at N = 20. We report on high statistics in-beam spectroscopy of 32 Mg with a unique approach, in that two direct reaction probes with different sensitivities to the underlying nuclear structure are employed at the same time. More specifically, states in 32 Mg were populated by knockout reactions starting from 33 Mg and 34 Si, lying inside and outside the island of inversion, respectively. The momentum distributions of the reaction residues and the cross sections leading to the individual final states were confronted with eikonal-based reaction calculations, yielding a significantly updated level scheme for 32 Mg and spin-parity assignments. By fully exploiting observables obtained in this measurement, a variety of structures coexisting in 32 Mg was unraveled. Comparisons with theoretical predictions based on shell-model overlaps allowed for clear discrimination between different structural models, revealing that the complete theoretical description of this key nucleus is yet to be achieved.

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Structure of Si33 and the magicity of the N=20 gap at Z=14

Cited by 10 publications

References 42 publications

In-beam $γ$-ray spectroscopy of $^{32}$Mg via direct reactions

In-beam $γ$-ray spectroscopy of $^{32}$Mg via direct reactions

Border of the Island of Inversion: Unbound states in $^{29}$Ne

Coexisting normal and intruder configurations in $^{32}$Mg

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