New structure information on 30Mg, 31Mg and 32Mg

Intermediate energy proton knockout to the “island of inversion” isotopeMg31

“…Most of these gamma rays have been seen in previous experiments [11,20,21]. The branching ratios and the energies of the gamma rays extracted from the current experiment agree well with these formerly established values.…”

“…6) that is evidence of a long lifetime and which is consistent with the previously measured half-life of 133(8) ps [20]. This corresponds to a traversal distance of 1.76(11) cm in the setup which results in a additional systematic uncertainty for the efficiency of about 10% which is not quoted in Table II…”

“…For the other excited states observed in the reaction, the AMD+GCM calculations [13] provides a useful insight into their nature together with previous experiments [11,20,21,29,30]. In particular, the neutron knockout experiment [11] populated the 3/2 − , 7/2 − states at 221 keV and 481 keV respectively labeled as 1p2h in the AMD+GCM calculation which agrees well with the removal of a fp-shell neutron from the 2p2h ground state of 32 Mg.…”

“…For the 171 keV decays to the 50 keV state, the ratio of counts of the forward to backward ring of SeGA differs from that of the 221 keV decay to the ground state by more than 4σ . Previous lifetime measurements [20] and Weisskopf estimates conclude these are dipole transitions, limiting the spin assignment of the 221 keV state to 1/2 or 3/2 given the known ground state spin of 1/2 + [10]. As these gamma rays originate from the same state, the distribution of magnetic substates of the initial level must be the same, and so the B λ are identical.…”

“…b Established values since measured values are subject to effects due to the previously measured lifetime of the state [20]. c Tentatively placed in the decay scheme based on energy balance.…”