Decoupling behavior in (132)La

Abstract

Heavy-ion fusion reactions (122)Sn((14,15)N, xn)(132)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)La has been theoretically investigated using the particle-rotor model in the model space of pi h(11/2) and (nu s(1/2), nu d(3/2)). The pseudospin coupling model was also utilized to understand the decoupling behavior in terms of the valence-particle configuration pi h(11/2)(Omega(pi) = 1/2) circle times nu[(411) over tilde](Omega(nu) = 1/2, 3/2), and a reasonable agreement with the experiment was obtained.