First observation of excited states in Cs114: Spectroscopy of the yrast ν(h11/2) π(h11/2) band

Excited states have been observed for the first time in the very neutron-deficient ${}_{55}^{114}{\mathrm{Cs}}_{59}$ nucleus. The assignment to $^{114}\mathrm{Cs}$ was made by detecting $\ensuremath{\gamma}$ rays in coincidence with evaporated charged particles and with recoiling evaporation residues. A rotational band has been observed up to spin $21\ensuremath{\hbar}$ (tentatively $25\ensuremath{\hbar}$). Excitation-energy systematics and a study of quasiparticle alignments suggest that the band is based on the $\ensuremath{\nu}({h}_{11/2})\ensuremath{\bigotimes}\ensuremath{\pi}({h}_{11/2})$ configuration. Unlike bands based on this configuration in heavier cesium isotopes, only one signature partner is observed, and there is no evidence for signature inversion. These observations agree with theoretical calculations which predict that Coriolis-induced signature splitting should dominate at $N=59$.