Description of nuclear octupole and quadrupole deformation close to the axial symmetry: Octupole vibrations in the X(5) nuclei 150Nd and 152Sm

TL;DR

This paper extends a nuclear model to describe octupole and quadrupole vibrations near axial symmetry, successfully accounting for both positive and negative parity states in 150Nd and 152Sm close to the phase transition point.

Contribution

It introduces a model that describes octupole vibrations near axial symmetry, accurately capturing negative parity states without altering the positive parity description.

Findings

Successfully describes negative-parity bands in 150Nd and 152Sm

Accurately reproduces positive parity levels and E2 transitions

Provides a unified description of octupole and quadrupole vibrations

Abstract

The model, introduced in a previous paper, for the description of the octupole and quadrupole degrees of freedom in conditions close to the axial symmetry, is used to describe the negative-parity band based on the first octupole vibrational state in nuclei close to the critical point of the U(5) to SU(3) phase transition. The situation of 150Nd and 152Sm is discussed in detail. The positive parity levels of these nuclei, and also the in-band E2 transitions, are reasonably accounted for by the X(5) model. With simple assumptions on the nature of the octupole vibrations, it is possible to describe, with comparable accuracy, also the negative parity sector, without changing the description of the positive-parity part.