First Spectroscopy of the Near Drip-line Nucleus 
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Crawford, H. L.; Fallon, P.; Macchiavelli, A. O.; Doornenbal, P.; Aoi, N.; Browne, F.; Campbell, C. M.; Chen, S; Clark, R. M.; Cortés, M. L.; Cromaz, M.; Ideguchi, E.; Jones, Michael D.; Kanungo, R.; MacCormick, M.; Momiyama, S.; Murray, I.; Nııkura, M.; Paschalis, S.; Petri, M.; Sakuraï, H.; Salathe, M.; Schrock, P.; Steppenbeck, D.; Takeuchi, S.; Tanaka, Y. K.; Taniuchi, R.; Wang, Handing; Wimmer, K.

doi:10.1103/physrevlett.122.052501

Cited by 79 publications

(58 citation statements)

References 33 publications

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“…At the end of investigation of the dipole resonances in nuclei with neutron excess, I discuss the strength distributions in neutron-rich exotic nuclei. The 40 Mg nucleus has attracted interest in a possible quadrupole deformation due to the broken spherical magic number of N = 28 near the drip line [58,59]. Theoretically, the deformation properties of the Mg isotopes close to the drip line have been explored by the Skyrme [60][61][62][63][64], Gogny [65], and relativistic [66] EDF approaches, and the GDR as well as the LED/PDR are predicted by the Skyrme EDF calculations [67,68].…”

Section: Amentioning

confidence: 99%

Charge-exchange dipole excitations in deformed nuclei

Yoshida

2020

Phys. Rev. C

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Background: The electric giant-dipole resonance (GDR) is the most established collective vibrational mode of excitation. A charge-exchange analog, however, has been poorly studied in comparison with the spin (magnetic) dipole resonance (SDR). Purpose: I investigate the role of deformation on the charge-exchange dipole excitations and explore the generic features as an isovector mode of excitation. Methods: The nuclear energy-density functional method is employed for calculating the response functions based on the Skyrme-Kohn-Sham-Bogoliubov method and the proton-neutron quasiparticle-random-phase approximation. Results: The deformation splitting into K = 0 and K = ±1 components occurs in the charge-changing channels and is proportional to the magnitude of deformation as is well known for the GDR. For the SDR, however, a simple assertion based on geometry of a nucleus cannot be applied for explaining the vibrational frequencies of each K component. A qualitative argument on the strength distributions for each component is given based on the non-energy-weighted sum rules taking nuclear deformation into account. The concentration of the electric dipole strengths in low energy and below the giant resonance is found in neutron-rich unstable nuclei. Conclusions: The deformation splitting occurs generically for the charge-exchange dipole excitations as in the neutral channel. The analog pygmy dipole resonance can emerge in deformed neutron-rich nuclei as well as in spherical systems.

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Section: Amentioning

confidence: 99%

Charge-exchange dipole excitations in deformed nuclei

Yoshida

2020

Phys. Rev. C

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“…[17] and proposed an excited 0 + 2 state based on the observed population cross section [18]. Approaching the drip line [19], the last N = 28 nucleus with excited states known is 40 Mg [20]. The measured two-proton removal cross sections along the N = 28 isotones [17,21] were interpreted as showing a change of the ground-state deformation from prolate in 44 S to oblate for 42 Si, and back to prolate at 40 Mg.…”

Section: Introductionmentioning

confidence: 99%

Shell structure of S43 and collapse of the N=28 shell closure

et al. 2020

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The single-particle structure of the N = 27 isotones provides insights into the shell evolution of neutron-rich nuclei from the doubly magic 48 Ca toward the drip line. 43 S was studied employing the one-neutron knockout reaction from a radioactive 44 S beam. Using a combination of prompt and delayed γ -ray spectroscopy the level structure of 43 S was clarified. Momentum distributions were analyzed and allowed for spin and parity assignments. The deduced spectroscopic factors show that the 44 S ground-state configuration has a strong intruder component. The results were confronted with shell-model calculations using two effective interactions. General agreement was found between the calculations, but strong population of states originating from the removal of neutrons from the 2p 3/2 orbital in the experiment indicates that the breakdown of the N = 28 magic number is more rapid than the theoretical calculations suggest.

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“…Specifically, the SDPF-U interaction [37] was designed to describe the physics inside the N = 28 island of inversion and has succeeded in reproducing excitation spectra in the high-Z part of this region [38]. The merging of the N = 28 and N = 20 islands of inversion is well described by the SDPF-U-MIX interaction [39], even though the predictions of the two interactions significantly differ in lighter isotopes [14,40].…”

Section: Introductionmentioning

confidence: 99%

Examining the N=28 shell closure through high-precision mass measurements of Ar46–48

et al. 2020

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The strength of the N = 28 magic number in neutron-rich argon isotopes is examined through high-precision mass measurements of 46-48 Ar, performed with the ISOLTRAP mass spectrometer at ISOLDE/CERN. The new mass values are up to 90 times more precise than previous measurements. While they suggest the persistence of the N = 28 shell closure for argon, we show that this conclusion has to be nuanced in light of the wealth of spectroscopic data and theoretical investigations performed with the SDPF-U phenomenological shell model interaction. Our results are also compared with ab initio calculations using the valence space in-medium similarity renormalization group and the self-consistent Green's function approaches. Both calculations provide a very good account of mass systematics at and around Z = 18 and, generally, a consistent description of the physics in this region. This combined analysis indicates that 46 Ar is the transition between the closed-shell 48 Ca and collective 44 S.

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First Spectroscopy of the Near Drip-line Nucleus Mg40

Cited by 79 publications

References 33 publications

Charge-exchange dipole excitations in deformed nuclei

Charge-exchange dipole excitations in deformed nuclei

Shell structure of S43 and collapse of the N=28 shell closure

Examining the N=28 shell closure through high-precision mass measurements of Ar46–48

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