N = 90 Shape Phase Transition: Increasing Axial Asymmetry Towards 148Ce

Abstract

In this proceedings the increasing axial asymmetry in the N = 90 isotopes with decreasing atomic number from 152 Sm to 148 Ce is shown. The placement of the nuclei of interest into the Interacting Boson Model symmetry triangle and the calculations of the approximate effective γ deformation shows the existence of some axial asymmetry, γ appr eff ≈ 10 • , in 148 Ce, while the N = 90 152 Sm does not show any. Moreover, the shape evolution study of the cerium, neodymium and samarium chains shows the over all increasing axially asymmetry with decreasing atomic number.KEY WORDS: Shape phase transition, N = 90, cerium isotopic chain, 148 Ce, γ degree of freedom, approximate effective γ deformation.