Doubly magic character of $^{78}$Ni - complex studies of simple nuclei

The neutron-rich, doubly-magic nucleus $^{78}$Ni and its neighbors are candidates for benchmarks that test nuclear structure models far from stability. According to shell-model calculations with effective interactions[e.g., 1], the large neutron excess in nuclei near $^{78}$Ni is expected to modify single-particle energies, which may lead to the weakening or disappearance of traditional shell-gaps. Moreover, these nuclei lie in a region of interest for nuclear astrophysics, since r-process nucleosynthesis is supposed to be initiated close to $^{78}$Ni [2]. Very little is known empirically about $^{78}$Ni.\\ Several experimental studies on neutron-rich Z$\sim$28 and 40