A first $\gamma$-ray study of ${}^{47,49}\mathrm{Cl}$ spectroscopy was performed at the Radioactive Isotope Beam Factory with ${}^{50}\mathrm{Ar}$ projectiles at 217 MeV/nucleon, impinging on the liquid hydrogen target of the MINOS device. Prompt deexcitation $\gamma$ rays were measured with the NaI(Tl) array DALI2${}^{+}$. Through the one-proton knockout reaction ${}^{50}\mathrm{Ar}(p,2p)$, a spin assignment could be determined for the low-lying states of ${}^{49}\mathrm{Cl}$ from the momentum distribution obtained with the SAMURAI spectrometer. A spin-parity $J^{\pi }=3/2^{+}$ is deduced for the ground state of ${}^{49}\mathrm{Cl}$, similar to the recently studied $N=32$ isotope ${}^{51}\mathrm{K}$. The evolution of the energy difference $E(1/2_1^{+})-E(3/2_1^{+})$ is compared to state-of-the-art theoretical predictions.

• Received 10 May 2021
• Revised 6 August 2021
• Accepted 30 September 2021

DOI:https://doi.org/10.1103/PhysRevC.104.044331