Recent investigations of exotic nuclei with N = 32 and 34 have highlighted the presence of sizable subshell closures at these neutron numbers that are absent in stable isotones. Indeed, the development of the shell gap at N = 32 is now well established from studies along the calcium, titanium, and chromium isotopic chains and, more recently, below the Z = 20 core in potassium and argon isotones. The onset of a new subshell closure at N = 34 was reported in 54Ca owing to the relatively high energy of its first 2+ state. On the theoretical side, the development of these neutron subshell gaps has been discussed, for example, in the framework of tensor-force-driven shell evolution; as protons are removed from the πf72 orbital, the vf52 state becomes progressively less bound and shifts up in energy relative to the vp32-vp12 spin-orbit partners. However, it was also reported that no significant N = 34 subshell gap exists in titanium, despite the fact that an inversion of the vf52 and vp12 orbitals has been noted. Thus, the strength of the N = 34 subshell closure in the scandium isotopes, which lie between calcium and titanium, provides additional insight on the migration of the vf52 orbital in exotic nuclei. In the present work, the low-lying structures of the neutron-rich isotopes 54Sc, 55Sc, and 56Sc - investigated using in-beam γ-ray spectroscopy with fast radioactive projectiles - will be presented, and the evolution of the N = 34 subshell closure will be further examined. The results will be compared to modern shell-model calculations applied within the pf shell.
|Journal||Proceedings of Science|
|Publication status||Published - Jan 1 2016|
|Event||26th International Nuclear Physics Conference, INPC 2016 - Adelaide, Australia|
Duration: Sep 11 2016 → Sep 16 2016
All Science Journal Classification (ASJC) codes