he evolution of the chiral symmetry in cesium isotopes

Following the reports of candidate chiral doublet bands observed in cesium isotopes, the possible chiral candidates and the evolution of three-dimensional rotation in $^{120-134}{ textrm{Cs}}$ are investigated within the microscopic three-dimensional tilted axis cranking covariant density functional theory (3DTAC-CDFT). By investigating the evolution of the polar angle $ theta$ and azimuth angle $ varphi$ as a function of rotational frequency $ hbar omega$, the transition from the planar rotation to the chiral rotation has been found in $^{121-133}{ textrm{Cs}}$. The corresponding critical rotational frequency $ omega_{ textrm{crit}}$ of the appearance of chiral aplanar rotation decreases as neutron number increases, which can be attributed to the neutrons in $(gd)$ and $(sd)$ shells having smaller angular momentum components along both the short and long axes, and larger components along medium axis, respectively. In comparison, only planar rotation has been obtained in $^{120,134}{ textrm{Cs}}$. With these interpretations, the obtained $I sim hbar omega$ and energy spectra as well as  $B(M1)/B(E2)$ values show reasonable agreement with the available experimental data. In addition, the evolution of quadrupole deformation $ beta$ and triaxial deformation $ gamma$ are also discussed.