High-spin states and possible chirality in the odd−ACs133 nucleus

Abstract

High-spin states of ${}^{133}\mathrm{Cs}$ have been studied using the fusion-evaporation reaction ${}^{130}\mathrm{Te}({}^7\mathrm{Li},4n){}^{133}\mathrm{Cs}$ at a beam energy of 32 MeV. The previously reported level scheme of ${}^{133}\mathrm{Cs}$ is extended and modified with the addition of nearly 30 new $\gamma$ transitions. A pair of nearly degenerate positive-parity doublet bands are identified and assigned the same $\pi d_{5/2}\otimes \nu h_{11/2}^{-2}$ configuration. The properties of both bands show general agreement with the fingerprints of chiral rotation, and thus the bands are suggested as candidate chiral doublet bands. This interpretation is also supported by the particle rotor model calculations. In addition, the high-$j$ intruder $\pi h_{11/2}$ band is extended to the $27/2^{-}$ state. A new decoupled $\mathrm{\Delta }I=2$ sequence and a weak positive-parity band with magnetic dipole $\left(M1\right)$ transitions are observed. The former is tentatively assigned the $\pi d_{5/2}{h}_{11/2}^2$ configuration. Meanwhile, the systematic studies of the $\pi d_{5/2}$, $\pi g_{7/2}$, and $\pi h_{11/2}$ bands in odd-$A$ Cs isotopes are also discussed in the present work.