Structure of the neutron-rich nucleus Mg30, which is located close to the region of the N=20 "island of inversion,"has been investigated by β-γ spectroscopy of spin-polarized Na30. From the detailed γ-γ coincidence relations, nine new states have been established in Mg30. The spin-polarization of Na30 enabled firm spin-parity assignments for seven states in Mg30 by means of the spatial asymmetry of β-ray counts in coincidence with the Mg30γ rays. Based on the experimental information, it is shown that various characteristic structures coexist in Mg30: (i) the ground-state vibrational-like band, (ii) the deformed band built on the 02+ state at 1.788 MeV, (iii) the γ-vibrational band built on the 23+ state at 3.543 MeV, and (iv) four states around 5 MeV associated with large β-transition probabilities: 1+ and 2+ states with spherical nature, 1+ and 2+ states with collective nature. The experimental results are compared with three theoretical calculations of the CHFB + LQRPA, the AMD + GCM, and the large-scale shell model with the EEdf1 interaction. All these theories reasonably reproduce the three bands.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics