Decoupling behavior inLa132

Abstract

Heavy-ion fusion reactions $^{122}\mathrm{Sn}$($^{14,15}\mathrm{N}$, $\mathit{xn}$)$^{132}\mathrm{La}$ have been utilized for the lifetime measurements using the recoil distance method. The lifetimes of seven low-lying excited states were obtained. In addition, the lifetimes of two states belonging to a band, which was identified as a decoupled band, were obtained. The decoupling behavior in $^{132}\mathrm{La}$ has been theoretically investigated using the particle-rotor model in the model space of $\ensuremath{\pi}{h}_{11/2}$ and ($\ensuremath{\nu}{s}_{1/2},$ $\ensuremath{\nu}{d}_{3/2}$). The pseudospin coupling model was also utilized to understand the decoupling behavior in terms of the valence-particle configuration $\ensuremath{\pi}{h}_{11/2}({\ensuremath{\Omega}}_{\ensuremath{\pi}}=\frac{1}{2})\ensuremath{\bigotimes}\ensuremath{\nu}[\mathrm{411\ifmmode \tilde{}\else \~{}\fi{}}]({\ensuremath{\Omega}}_{\ensuremath{\nu}}=\frac{1}{2},\frac{3}{2})$, and a reasonable agreement with the experiment was obtained.