Search for two‐proton radioactivity of 19Mg in a tracking experiment

The two‐proton radioactivity of the previously unknown 19Mg ground‐state is observed by tracking the decay products in‐flight. The trajectories of the 2p‐decay products, 17Ne+p+p, have been measured by using tracking micro‐strip detectors which allowed to reconstruct the 2p‐decay vertices and fragment correlations. The half‐life of 19Mg deduced from the measured vertex distribution is 4.0(15) ps in the system of 19Mg. The Q‐value of the 2p‐decay of the 19Mg ground‐state inferred from the measured p−p−17Ne correlations is 0.75(5) MeV.