Lifetime Measurements and Triple Coexisting Band Structure in 43S

Lifetime measurements of excited states in the neutron-rich nucleus S-43 were performed by applying the recoil-distance method on fast rare-isotope beams in conjunction with the Gamma-Ray Energy Tracking In-beam Nuclear Array. The new data based on gamma gamma coincidences and lifetime measurements resolve a doublet of (3/2(-)) and (5/2(-)) states at low excitation energies. Results were compared to the posdthorn pi(sd) - nu(pf) shell model and antisymmetrized molecular dynamics calculations. The consistency with the theoretical calculations identifies a possible appearance of three coexisting bands near the ground state of S-43: the K-pi =1/2(-) band built on a prolate-deformed ground state, a band built on an isomer with a 1f(7/2)(-1) character, and a suggested excited band built on a newly discovered doublet state. The latter further confirms the collapse of the N = 28 shell closure in the neutron-rich region.