The excitation energy of the lowest-energy superdeformed band in ${}^{196}\mathrm{Pb}$ is established using the techniques of time-correlated $\gamma$-ray spectroscopy. Together with previous measurements on ${}^{192}\mathrm{Pb}$ and ${}^{194}\mathrm{Pb}$, this result allows superdeformed excitation energies, binding energies, and two-proton and two-neutron separation energies to be studied systematically, providing stringent tests for current nuclear models. The results are examined for evidence of a “superdeformed shell gap.”

• Received 6 May 2005

DOI:https://doi.org/10.1103/PhysRevLett.95.182501