In-beam γ-ray spectroscopy of nuclei in the ~(132)Sn region performed at RIKEN

摘要

The nucleus ~(133)Sn_(83), with one single neutron outside doubly-magic ~(132)Sn, was studied at the Radioactive Isotope Beam Factory at RIKEN. The excited states of ~(133)Sn were populated via one-neutron knockout from a ~(134)Sn beam on a carbon target at relativistic energies. Besides the γ rays emitted following the decay of known neutron single-particle states, additional γ strength above the neutron separation energy was observed for the first time. It has been interpreted as evidence for a competition between γ-ray and neutron emission in the decay of neutronunbound states in ~(133)Sn.