Low spin spectroscopy of neutron-rich ${}_{43,44,45}\mathrm{Cl}$ via ${\beta }^{-}$ and $\beta n$ decay

In this article, ${\beta }^{-}$ decay studies of neutron-rich isotopes ${}_{43,45}S$ performed at the National Superconducting Cyclotron Laboratory are reported. $\beta$-delayed $\gamma$ transitions were detected by an array of 16 clover detectors surrounding the Beta Counting Station, which consists of a $40\times 40$ double-sided silicon strip detector followed by a single-sided silicon strip detector. $\beta$-decay half-lives were extracted for ${}_{43,45}S$ by correlating implants and decays in the pixelated implant detector and by considering further coincidences with $\gamma$ transitions in the daughter nuclei. The level structures of ${}_{43,45}\mathrm{Cl}$ are expanded by the addition of 20 and 8 new $\gamma$ transitions in ${}_{43}\mathrm{Cl}$ and ${}_{45}\mathrm{Cl}$ respectively, and core-excited negative-parity states were observed in both nuclei for the first time. For ${}_{45}S$, a large fraction of the $\beta$-decay strength was observed feeding neutron-unbound states in ${}_{45}\mathrm{Cl}$, which, decaying by delayed neutrons, populated excited states in the $\beta 1n$ daughter, ${}_{44}\mathrm{Cl}$. Experimental observations were compared to detailed shell-model calculations using the SDPFSDG-MU interaction to highlight the role of the diminished $N=28$ neutron shell gap and the near degeneracy of the proton $s_{1/2}$ and $d_{3/2}$ orbitals in the structure of the neutron-rich Cl isotopes. The current work also provides further support to a ground-state spin-parity assignment of $3/2^{+}$ in ${}_{45}\mathrm{Cl}$.