Highest spin discrete levels in $^{131,132}Ce$: Spin generation near the mesoscopic limit

The three superdeformed (SD) bands in $^{132}Ce$ and the two SD bands in $^{131}Ce$ have been extended to higher spin, following experiments with the Euroball IV spectrometer. The two SD bands in $^{131}Ce$ have been linked together. However, despite the relatively high population intensity of the bands (up to 5\% of the respective channel), it has not been possible to unambiguously link any of the five SD bands into the low-spin, normally deformed structures of $^{131,132}Ce$. At the highest spins ($>60hbar$), some of the bands exhibit the characteristic behavior of smooth band termination, i.e., energetically costly angular-momentum generation near the finite mesoscopic limit. Configuration-dependent cranked Nilsson-Strutinsky calculations have been performed to suggest single-particle configurations for the SD bands and to investigate the possibility of termination in these bands.