Detailed study of the decay of 21Mg

Beta-delayed proton and gamma emission in the decay of $$^{21}$$Mg has been measured at ISOLDE, CERN with the ISOLDE Decay Station (IDS) set-up. The existing decay scheme is updated, in particular what concerns proton transitions to excited states in $$^{20}$$Ne. Signatures of interference in several parts of the spectrum are used to settle spin and parity assignments to highly excited states in $$^{21}$$Na. The previously reported $$\beta $$p$$\alpha $$branch is confirmed. A half-life of 120.5(4) ms is extracted for $$^{21}$$Mg. The revised decay scheme is employed to test mirror symmetry in the decay and to extract the beta strength distribution of $$^{21}$$Mg that is compared with theory.