Studying the doublet bands at the borders of the $A \approx 130$ island of chiral candidates: the $^{120}$I case

Abstract

Based on the reported positive-parity doublet bands in $^{120}$I, the corresponding experimental characteristics including rotational alignment have been discussed and corresponding configuration assignment is reexamined. The self-consistent tilted axis cranking relativistic mean-field calculations indicates that this doublet bands is built on configuration $\pi h_{11/2}\otimes \nu h ^{-1}_{11/2}$. In addition, adopting the two quasiparticles coupled with a triaxial rotor model, the excitation energies, energy staggering parameter $S(I)$, $B(M1)/B(E2)$, effective angles, and $K$ $plots$ have been discussed and also compared with the available data. All of these results support the interpretation of chiral doublet bands for the positive-parity doublet bands in $^{120}$I, and hence identify this nucleus as the border of the $A \approx 130$ island of chiral candidates.