Shell evolution approaching the 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>N</mml:mi><mml:mo>=</mml:mo><mml:mn>20</mml:mn></mml:mrow></mml:math>
 island of inversion: Structure of 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Mg</mml:mi><mml:mprescripts /><mml:none /><mml:mn>29</mml:mn></mml:mmultiscripts></mml:math>

Matta, A.; Catford, W. N.; Orr, N. A.; Henderson, J.; Ruotsalainen, P.; Hackman, G.; Garnsworthy, A. B.; Delaunay, F.; Wilkinson, R.; Lotay, G.; Tsunoda, Naofumi; Otsuka, Takaharu; Knapton, A.; Ball, G. C.; Bernier, N.; Burbadge, C.; Chester, A.; Cross, D. S.; Cruz, S.; Diget, C. Aa.; Domingo, T.; Drake, T.E.; Evitts, L. J.; Garcia, F. H.; Hallam, S.; MacConnachie, E.; Moukaddam, M.; Muecher, D.; Padilla‐Rodal, E.; Paetkau, O.; Park, J.; Pore, J. L.; Rizwan, U.; Smallcombe, J.; Smith, J. K.; Starosta, K.; Svensson, C. E.; Williams, Jonathan; Williams, M.

doi:10.1103/physrevc.99.044320

Cited by 11 publications

(16 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In these experiments, TIGRESS was composed of 12 HPGe clover detectors arranged in a compact hemispherical arrangement with approximately 2π steradians geometrical coverage (see Fig. 2 of [39]). The individual crystals contain an electrical core contact and eight-fold electrical segmentation on the outer contact; four quadrants and a lateral divide, giving an overall 32-fold segmentation within each clover.…”

Section: Experimental Setup and Conditionsmentioning

confidence: 99%

Single-particle structure of neutron-rich Sr isotopes via H2(Sr94,95,96,

Cruz¹,

Wimmer²,

Bender³

et al. 2019

Phys. Rev. C

Self Cite

View full text Add to dashboard Cite

Background: The region around neutron number N = 60 in the neutron-rich Sr and Zr nuclei is one of the most dramatic examples of a ground state shape transition from (near) spherical below N = 60 to strongly deformed shapes in the heavier isotopes.Purpose: The single-particle structure of 95−97 Sr approaching the ground state shape transition at 98 Sr has been investigated via single-neutron transfer reactions using the (d, p) reaction in inverse kinematics. These reactions selectively populate states with a large overlap of the projectile ground state coupled to a neutron in a single-particle orbital.Method: Radioactive 94,95,96 Sr nuclei with energies of 5.5 AMeV were used to bombard a CD2 target. Recoiling light charged particles and γ rays were detected using a quasi-4π silicon strip detector array and a 12 element Ge array. The excitation energy of states populated was reconstructed employing the missing mass method combined with γ-ray tagging and differential cross sections for final states were extracted.Results: A reaction model analysis of the angular distributions allowed for firm spin assignments to be made for the low-lying 352, 556 and 681 keV excited states in 95 Sr and a constraint has been placed on the spin of the higher-lying 1666 keV state. Angular distributions have been extracted for 10 states populated in the d( 95 Sr, p) 96 Sr reaction, and constraints have been provided for the spins and parities of several final states. Additionally, the 0, 167 and 522 keV states in 97 Sr were populated through the d( 96 Sr, p) reaction. Spectroscopic factors for all three reactions were extracted. Conclusions:Results are compared to shell model calculations in several model spaces and the structure of low-lying states in 94 Sr and 95 Sr is well-described. The spectroscopic strength of the 0 + and 2 + states in 96 Sr is significantly more fragmented than predicted. The spectroscopic factors for the d( 96 Sr, p) 97 Sr reaction suggest that the two lowest lying excited states have significant overlap with the weakly deformed ground state of 96 Sr, but the ground state of 97 Sr has a different structure. * Corresponding author: wimmer@phys.s.u-tokyo.ac.jp arranging the nucleons in certain ways across the valence orbitals, which in turn causes a departure from sphericity [1]. The expense of such re-arrangements is dependent on the size of the energy gaps between single-particle orbitals above the Fermi energy. If the energy spacing is small, the valence nucleons can scatter into valence orbitals which are above the Fermi energy and drive the nucleus into a low-energy deformed configuration. On the other hand, if the energy spacing is large, the valence nucleons are unable to scatter into higher orbitals and this favors spherical shapes. The size of these energy gaps is in turn dependent on the number of valence nucleons, due to the monopole component of the residual

show abstract

Section: Experimental Setup and Conditionsmentioning

confidence: 99%

Single-particle structure of neutron-rich Sr isotopes via H2(Sr94,95,96,

Cruz¹,

Wimmer²,

Bender³

et al. 2019

Phys. Rev. C

Self Cite

View full text Add to dashboard Cite

show abstract

“…Fitted angular distribution data is shown in Figure 4. For some high-lying transitions with low statistics, the only information provided by the angular distribution was whether the distribution was peaked at 90 • (a 2 < 0) Gamma-ray energy (keV) a2 a4 a2(a4 = 0) 1163.1 (4) 0.6(5) 0.1(6) 0.5(3) 2506.7 (8) 0.0(4) 0.1(5) -0.1(3) 2547. 6(3) 0.20(10) -0.19(13) 3082.5 (12) 0.7(5) 0.6(5) 3726 2-0.3(6) 0.0(7) -0.3(4) 3907.…”

Section: B Angular Distributionsmentioning

confidence: 99%

“…The N = 20 IoI is one of many regions of neutron shell breaking, with recent evidence suggesting that the neutron rich side of the N = 20 IoI merges with the N = 28 IoI for Mg isotopes [4]. In addition to investigating the boundaries of the IoI, recent experiments have studied shell evolution in Na and Mg isotopes approaching the IoI [5][6][7][8]. Determining the onset of the IoI requires the identification and investigation of intruder orbitals as a function of neutron excess.…”

Section: Introductionmentioning

confidence: 99%

Structure of Mg28 and influence of the neutron pf shell

et al. 2019

Self Cite

View full text Add to dashboard Cite

Gamma-ray spectroscopy and lifetime measurements using the Doppler Shift Attenuation Method (DSAM) were performed on the nucleus 28 Mg near the N = 20 'island of inversion', which was populated using a 12 C(18 O,2p) 28 Mg fusion-evaporation reaction to investigate the impact of shell evolution on its high-lying structure. Three new levels were identified at 7203(3), 7747(2), and 7929.3(12) keV along with several new gamma rays. A newly extracted B(E2; 4 + 1 → 2 + 1) of 42(7) e 2 fm 4 indicates reduced collectivity in the yrast band at high spin, consistent with ab initio SA-NCSM calculations. At high excitation energy, evidence for the population of intruder orbitals was obtained through identification of negative parity levels (I π = (0, 4) − , (4, 5) −). Calculations using the SDPF-MU interaction indicate that these levels arise from single neutron excitation to the pf shell and provides evidence for the lowering of these intruder orbitals approaching the 'island of inversion'.

show abstract

“…From these data, it is concluded in Ref. [32] that the ground state of 51 K must be a 3/2 + state that is dominated by the π(d 3/2 ) −1 configuration. The predicted reinversion has thus been confirmed by experiment.…”

Section: From N = 28 To N = 32 and Beyondmentioning

confidence: 93%

“…In Figure 4, the energies of the 1/2 + 1 levels, measured from the 3/2 + 1 levels in neutron-rich K isotopes, are compared to theory. Very recently, the first excited levels in 51,53 K (N = 32, 34) were measured to be 0.74 and 0.84 MeV, respectively [33]. These states are assigned to be 1/2 + from the observed parallel momentum distributions of the 51,53 K residues after (p, 2p) reactions.…”

Section: From N = 28 To N = 32 and Beyondmentioning

confidence: 99%

Probing Different Characteristics of Shell Evolution Driven by Central, Spin-Orbit, and Tensor Forces

Utsuno

2022

Physics

View full text Add to dashboard Cite

In this paper, the validity of the shell-evolution picture is investigated on the basis of shell-model calculations for the atomic mass number 25≲A≲55 neutron-rich nuclei. For this purpose, the so-called SDPF-MU interaction is used. Its central, two-body spin–orbit, and tensor forces are taken from a simple Gaussian force, the M3Y (Michigan 3-range Yukawa) interaction, and a π+ρ meson exchange force, respectively. Carrying out almost a complete survey of the predicted effective single-particle energies, it is confirmed here that the present scheme is quite effective for describing shell evolution in exotic nuclei.

show abstract

Shell evolution approaching the N=20 island of inversion: Structure of Mg29

Cited by 11 publications

References 48 publications

Single-particle structure of neutron-rich Sr isotopes via H2(Sr94,95,96,

Single-particle structure of neutron-rich Sr isotopes via H2(Sr94,95,96,

Structure of Mg28 and influence of the neutron pf shell

Probing Different Characteristics of Shell Evolution Driven by Central, Spin-Orbit, and Tensor Forces

Contact Info

Product

Resources

About