Observation of the lowest energy gamma-ray in any superdeformed nucleus   : 196Bi
  New results on the superdeformed $^{196}$Bi nucleus a re reported. We have observed with the EUROBALL IV $\gamma$-ray spectrometer array a superdeformed trans ition of 124 keV which is the lowest observed energy $\gamma$-ray in any superdeformed nucleus. We have de velopped microscopic cranked Hartree-Fock-Bogoliubov calculations using the SLy4 effective force and a realistic surface p airing which strongly support the $K^\pi=2^-$($\pi$[651]1/2$\otimes \nu$[752]5/2) assignment of this su perdeformed band. 
A. Prevost (CSNSM, Ipnl), B. Rosse (IPNL), M. Meyer (IPNL), N. Redon   (IPNL), C. Schmitt (IPNL), O. Stezowski (IPNL), P. La...