How Robust is the N= 34 Subshell Closure? First Spectroscopy of Ar 52 - Liu, HN; Obertelli, A; Doornenbal, P; Bertulani, C.A.; Hagen, G; Holt, JD; Jansen, GR; Morris, TD; Schwenk, A; Stroberg, R; others (Physical review letters, 2019)