Discovery of a new isomeric state in $^{68}$Ni: Evidence for a highly-deformed proton intruder state
nucl-ex
/ Authors
A. Dijon, E. Clément, G. De France, G. De Angelis, G. Duchêne, J. Dudouet, S. Franchoo, A. Gadea, A. Gottardo, T. Hüyük
and 19 more authors
B. Jacquot, A. Kusoglu, D. Lebhertz, G. Lehaut, M. Martini, D. R. Napoli, F. Nowacki, S. Péru, A. Poves, F. Recchia, N. Redon, E. Sahin, C. Schmitt, M. Sferrazza, K. Sieja, O. Stezowski, J. J. Valiente-Dobon, A. Vancraeyenest, Y. Zheng
/ Abstract
We report on the observation of a new isomeric state in $^{68}$Ni. We suggest that the newly observed state at 168(1) keV above the first 2$^+$ state is a $π(2p-2h)$ 0$^{+}$ state across the major Z=28 shell gap. Comparison with theoretical calculations indicates a pure proton intruder configuration and the deduced low-lying structure of this key nucleus suggests a possible shape coexistence scenario involving a highly deformed state.