Nuclear structure along the Z = 28 and Z = 50 shells Shell evolution and shape coexistence in 74,76,78Cu and 126Sn

Abstract

How does the structure of neutron-rich atomic nuclei change when moving away from stability? Here, both single-particle and collective effects are studied by using two case studies: the chain of neutron-rich copper isotopes and the chain of tin isotopes - from stable to neutron-rich. The nuclear structure of the exotic nuclei copper-74, 76, and 78 was studied for the first time. The highly unstable copper isotopes were created through fission and beta-decay. During decays towards their ground states, they emit gamma radiation with discrete, distinctive energies. The inner structure of the copper isotopes was investigated by measuring the emitted gamma rays. The chain of tin isotopes exhibits a phenomenon called shape coexistence. This means that a single nucleus can take on different geometrical shapes based on its energy level. In all the stable tin isotopes with an even number of protons and neutrons, shape coexistence between spherical and deformed 0+ states is known. The presence of an excited 0+ state has been found for the first time in tin-126, the next even nucleus in the isotopic chain after the stable ones.