New states in 18Na and 19Mg observed in the two-proton decay of 19Mg

Abstract

Previously unknown states in 18Na and 19Mg have been studied by measuring the trajectories of their decay products with microstrip detectors. Analyzing angular correlations of the fragments provided information on decay energies and widths of the parent states. The ground state of 18Na has been detected and its one-proton decay energy of 1.23(15) MeV determined. Four previously unknown states in 19Mg at 2.1, 2.9, 3.6, and 5.2 MeV have been observed. The competition between simultaneous and sequential two-proton emission of states in 19Mg is discussed, and the conclusion of a direct mechanism of 2p radioactivity of the 19Mg ground state is confirmed. © 2012 American Physical Society.