Investigating Shell Structure at the N=34 Shell Gap

The nuclear shell model is a phenomenological model that allows for accurate predictions of nuclear binding energies, spins, and parities in many situations. Additionally, a large contribution of the shell model is its prediction of magic numbers, which occur when nuclei have completely filled shells where both or either nucleon number is 2, 8, 20, 28, 50, 82, or 126. Nuclei possessing magic numbers typically exhibit more stable configurations against nuclei that do not, meaning the energy for the first excited state in magic nuclei is larger than non-magic nuclei, making magic nuclei harder to excite. When moving away from the valley of stability, towards neutron-rich nuclei, new magic numbers, such as N=34, are favored more than the standard magic numbers. One such example is ⁵⁴Ca, which exhibits doubly-magic characteristics for N=34 and Z=20 with a large energy for the first excited state, providing evidence for new shell gaps. At Florida State University, a fusion evaporation reaction done with a ¹⁸O beam onto a ⁵⁰Ti target, residue nuclei, such as ⁶⁴Zn, were studied to provide more insight into the N=34 shell gap. While ⁶⁴Zn is not “nuetron-rich”, investigating its energy transitions at high spin states can draw analogous conclusions for the transitions in nuclei like ⁵⁴Ca and will be presented.