Abstract
The low-lying structure of Sc55 has been investigated using in-beam γ-ray spectroscopy with the Be9(Ti56,Sc55+γ)X one-proton removal and Be9(Sc55,Sc55+γ)X inelastic-scattering reactions at the RIKEN Radioactive Isotope Beam Factory. Transitions with energies of 572(4), 695(5), 1539(10), 1730(20), 1854(27), 2091(19), 2452(26), and 3241(39) keV are reported, and a level scheme has been constructed using γγ coincidence relationships and γ-ray relative intensities. The results are compared to large-scale shell-model calculations in the sd-pf model space, which account for positive-parity states from proton-hole cross-shell excitations, and to ab initio shell-model calculations from the in-medium similarity renormalization group that includes three-nucleon forces explicitly. The results of proton-removal reaction theory with the eikonal model approach were adopted to aid identification of positive-parity states in the level scheme; experimental counterparts of theoretical 1/21+ and 3/21+ states are suggested from measured decay patterns. The energy of the first 3/2- state, which is sensitive to the neutron shell gap at the Fermi surface, was determined. The result indicates a rapid weakening of the N=34 subshell closure in pf-shell nuclei at Z>20, even when only a single proton occupies the πf7/2 orbital.
| Original language | English |
|---|---|
| Article number | 064310 |
| Journal | Physical Review C |
| Volume | 96 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Dec 11 2017 |
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All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
Cite this
Structure of Sc 55 and development of the N=34 subshell closure. / Steppenbeck, D.; Takeuchi, S.; Aoi, N.; Doornenbal, P.; Matsushita, M.; Wang, H.; Baba, H.; Go, Shintaro; Holt, J. D.; Lee, J.; Matsui, K.; Michimasa, S.; Motobayashi, T.; Nishimura, D.; Otsuka, T.; Sakurai, H.; Shiga, Y.; Söderström, P. A.; Stroberg, S. R.; Sumikama, T.; Taniuchi, R.; Tostevin, J. A.; Utsuno, Y.; Valiente-Dobón, J. J.; Yoneda, K.
In: Physical Review C, Vol. 96, No. 6, 064310, 11.12.2017.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Structure of Sc 55 and development of the N=34 subshell closure
AU - Steppenbeck, D.
AU - Takeuchi, S.
AU - Aoi, N.
AU - Doornenbal, P.
AU - Matsushita, M.
AU - Wang, H.
AU - Baba, H.
AU - Go, Shintaro
AU - Holt, J. D.
AU - Lee, J.
AU - Matsui, K.
AU - Michimasa, S.
AU - Motobayashi, T.
AU - Nishimura, D.
AU - Otsuka, T.
AU - Sakurai, H.
AU - Shiga, Y.
AU - Söderström, P. A.
AU - Stroberg, S. R.
AU - Sumikama, T.
AU - Taniuchi, R.
AU - Tostevin, J. A.
AU - Utsuno, Y.
AU - Valiente-Dobón, J. J.
AU - Yoneda, K.
PY - 2017/12/11
Y1 - 2017/12/11
N2 - The low-lying structure of Sc55 has been investigated using in-beam γ-ray spectroscopy with the Be9(Ti56,Sc55+γ)X one-proton removal and Be9(Sc55,Sc55+γ)X inelastic-scattering reactions at the RIKEN Radioactive Isotope Beam Factory. Transitions with energies of 572(4), 695(5), 1539(10), 1730(20), 1854(27), 2091(19), 2452(26), and 3241(39) keV are reported, and a level scheme has been constructed using γγ coincidence relationships and γ-ray relative intensities. The results are compared to large-scale shell-model calculations in the sd-pf model space, which account for positive-parity states from proton-hole cross-shell excitations, and to ab initio shell-model calculations from the in-medium similarity renormalization group that includes three-nucleon forces explicitly. The results of proton-removal reaction theory with the eikonal model approach were adopted to aid identification of positive-parity states in the level scheme; experimental counterparts of theoretical 1/21+ and 3/21+ states are suggested from measured decay patterns. The energy of the first 3/2- state, which is sensitive to the neutron shell gap at the Fermi surface, was determined. The result indicates a rapid weakening of the N=34 subshell closure in pf-shell nuclei at Z>20, even when only a single proton occupies the πf7/2 orbital.
AB - The low-lying structure of Sc55 has been investigated using in-beam γ-ray spectroscopy with the Be9(Ti56,Sc55+γ)X one-proton removal and Be9(Sc55,Sc55+γ)X inelastic-scattering reactions at the RIKEN Radioactive Isotope Beam Factory. Transitions with energies of 572(4), 695(5), 1539(10), 1730(20), 1854(27), 2091(19), 2452(26), and 3241(39) keV are reported, and a level scheme has been constructed using γγ coincidence relationships and γ-ray relative intensities. The results are compared to large-scale shell-model calculations in the sd-pf model space, which account for positive-parity states from proton-hole cross-shell excitations, and to ab initio shell-model calculations from the in-medium similarity renormalization group that includes three-nucleon forces explicitly. The results of proton-removal reaction theory with the eikonal model approach were adopted to aid identification of positive-parity states in the level scheme; experimental counterparts of theoretical 1/21+ and 3/21+ states are suggested from measured decay patterns. The energy of the first 3/2- state, which is sensitive to the neutron shell gap at the Fermi surface, was determined. The result indicates a rapid weakening of the N=34 subshell closure in pf-shell nuclei at Z>20, even when only a single proton occupies the πf7/2 orbital.
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U2 - 10.1103/PhysRevC.96.064310
DO - 10.1103/PhysRevC.96.064310
M3 - Article
VL - 96
JO - Physical Review C
JF - Physical Review C
SN - 2469-9985
IS - 6
M1 - 064310
ER -