Semi-microscopic description of the backbending phenomena in some deformed even-even nuclei

TL;DR

This paper presents a semi-microscopic model combining particle interactions and a deformed core to explain backbending phenomena in certain deformed even-even nuclei, achieving good agreement with experimental data.

Contribution

It introduces a hybrid model of two interacting rotational bands using a semi-phenomenological approach, integrating particle and core dynamics for backbending analysis.

Findings

The model accurately reproduces backbending in six nuclei.

Good agreement between theoretical predictions and experimental data.

The formalism captures the interaction between particle pairs and the core.

Abstract

The mechanism of backbending is semi-phenomenologically investigated based on the hybridization of two rotational bands. These bands are defined by treating a model Hamiltonian describing two interacting subsystems: a set of particles moving in a deformed mean field and interacting among themselves through an effective pairing force and a phenomenological deformed core whose intrinsic ground state is an axially symmetric coherent boson state. The two components interact with each other by a quadrupole-quadrupole and a spin-spin interaction. The total Hamiltonian is considered in the space of states with good angular momentum, projected from a quadrupole deformed product function. The single-particle factor function defines the nature of the rotational bands, one corresponding to the ground band in which all particles are paired and another one built upon a $i_{13/2}$ neutron broken pair. The formalism is applied to six deformed even-even nuclei, known as being good backbenders. Agreement between theory and experiment is fairly good.