Publication Type
Journal
Journal Name
Physical Review Letters
Publication Date
Page Number
072502
Volume
122
Issue
7
Abstract
The first γ-ray spectroscopy of 52Ar, with the neutron number N=34, was measured using the 53K(p,2p) one-proton removal reaction at ∼210 MeV/u at the RIBF facility. The 2+1 excitation energy is found at 1656(18) keV, the highest among the Ar isotopes with N>20. This result is the first experimental signature of the persistence of the N=34 subshell closure beyond 54Ca, i.e., below the magic proton number Z=20. Shell-model calculations with phenomenological and chiral-effective-field-theory interactions both reproduce the measured 2+1 systematics of neutron-rich Ar isotopes, and support a N=34 subshell closure in 52Ar.
