Discovery of a new isomeric state in $^{68}$Ni: Evidence for a   highly-deformed proton intruder state
  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 $\pi(2p-2h)$ 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. 
A. Dijon (GANIL), E. Cl\'ement (GANIL), G. De France (GANIL), G. De   Angelis, G. Duch\^ene (IPHC), J. Dudouet (GANIL), S. F...
nucl-ex