${\beta }^{-}$ decay of very neutron-rich isotopes of P and S, studied at the National Superconducting Cyclotron Laboratory using the Beta Counting Station consisting of a Double Sided Strip Detector surrounded by clovers detectors for observing delayed $\gamma$ transitions, is reported here. $\beta$-decay half-lives and delayed neutron emission probabilities were extracted for ${}^{42,43,44}\mathrm{P}$ and ${}^{44,46}\mathrm{S}$ by analyzing spatial and temporal correlations between implants and decay events in the Si detector with further coincidence with $\gamma$ transitions. Detection of delayed $\gamma$ rays allowed for the identification of negative-parity 1p1h states in ${}^{42}\mathrm{S}$ for the first time, also constraining the parent (${}^{42}\mathrm{P}$) spin/parity to $2^{-}\text{or}{3}^{-}$. For the most exotic isotope studied, ${}^{46}\mathrm{S}$, no strong $\gamma$ transition was observed unlike lighter even-even S isotopes, thus implying the shift of Gamow-Teller strength distribution to higher energies. Comparison of experimental observations to detailed shell-model calculations using the SDPFSDG-MU interaction allowed us to infer the importance and role of first forbidden $\beta$ transitions as the neutron number approaches and then exceeds $N=28$.

• Received 24 September 2022
• Accepted 28 November 2022

DOI:https://doi.org/10.1103/PhysRevC.106.064314