Octupole degree of freedom for the critical-point candidate nucleus<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Sm</mml:mi><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>152</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>in a reflection-asymmetric relativistic mean-field approach

Abstract

The potential energy surfaces of even-even $^{146-156}$Sm are investigated in the constrained reflection-asymmetric relativistic mean-field approach with parameter set PK1. It is shown that the critical-point candidate nucleus $^{152}$Sm marks the shape/phase transition not only from U(5) to SU(3) symmetry, but also from the octupole-deformed ground state in $^{150}$Sm to the quadrupole-deformed ground state in $^{154}$Sm. By including the octupole degree of freedom, an energy gap near the Fermi surface for single-particle levels in $^{152}$Sm with $\beta_2 = 0.14 \sim 0.26$ is found, and the important role of the octupole deformation driving pair $\nu 2f_{7/2}$ and $\nu 1i_{13/2}$ is demonstrated.

Locations

• Physical Review C - View
• arXiv (Cornell University) - View - PDF
• DataCite API - View