Update on the Complete Decay Spectroscopy of ⁵⁴Ca and ⁵⁵Sc: Probing Nuclear Structure Near N = 34.

The first complete decay spectroscopy of ⁵⁴Ca and ⁵⁵Sc was performed at the Facility for Rare Isotope Beams (FRIB) using an experimental setup that enabled the simultaneous detection β-delayed of γ rays and neutrons. This configuration facilitated extraction of the β-decay strength over a wide range of excitation energies, including neutron-unbound states. We observed neutron emission and multiple γ transitions following the decay of ⁵⁴Ca to ⁵⁴Sc and ⁵⁵Sc to ⁵⁵Ti, allowing for decay scheme reconstruction and β-feeding analysis. This work aims to probe the proposed N = 34 subshell closure, whose persistence still an open question. While ⁵⁴Ca shows signatures of a gap at N = 34, the evolution of nuclear structure beyond Z = 20 is not well established. With a single proton in the πf7/2 orbital, ⁵⁵Sc provides a sensitive probe of proton-neutron interactions that alter the neutron single-particle energies. These results offer new constraints on shell-model calculations in the neutron-rich fp-shell region and contribute to a broader understanding of shell evolution far from stability.