Observation of two-proton radioactivity of Mg19 by tracking the decay products

Abstract

We have observed the two-proton radioactivity of the previously unknown Mg19 ground state by tracking the decay products in-flight. For the first time, the trajectories of the 2p-decay products, Ne17+p+p, have been measured by using tracking microstrip detectors which allowed us to reconstruct the 2p-decay vertices and fragment correlations. The half-life of Mg19 deduced from the measured vertex distribution is 4.0(15)ps in the system of Mg19. The Q value of the 2p decay of the Mg19 ground state inferred from the measured p-p-Ne17 correlations is 0.75(5)MeV. © 2007 The American Physical Society.