Collectivity in the light Xenon isotopes: A shell model study

TL;DR

This study uses the Interacting Shell Model to analyze the collectivity and deformation in light Xenon isotopes, providing predictions for unknown nuclei and exploring pairing and alignment effects on nuclear structure.

Contribution

The paper offers a detailed shell model analysis of light Xenon isotopes, including predictions for 108-Xe and insights into pairing and alignment phenomena.

Findings

Collective triaxial structures match experimental data.

Backbending caused by particle alignment in the 0h11/2 orbit.

Role of isovector and isoscalar pairing in yrast band structures.

Abstract

The lightest Xenon isotopes are studied in the framework of the Interacting Shell Model (ISM). The valence space comprises all the orbits lying between the magic closures N=Z=50 and N=Z=82. The calculations produce collective deformed structures of triaxial nature that encompass nicely the known experimental data. Predictions are made for the (still unknown) N=Z nucleus 108-Xe. The results are interpreted in terms of the competition between the quadrupole correlations enhanced by the pseudo-SU(3) structure of the positive parity orbits and the pairing correlations brought in by the 0h11/2 orbit. We have studied as well the effect of the excitations from the 100-Sn core on our predictions. We show that the backbending in this region is due to the alignment of two particles in the 0h11/2 orbit. In the N=Z case, one neutron and one proton align to J=11 and T=0. In 110-Xe and 112-Xe the alignment begins in the J=10 T=1 channel and it is dominantly of neutron neutron type. Approaching the band termination the alignment of a neutron and a proton to J=11 and T=0 takes over. In a more academic mood, we have explored the role of the isovector and isoscalar pairing correlations on the structure on the yrast bands of 108-Xe and 110-Xe and examined the role of the isovector and isoscalar pairing condensates in these N~Z nuclei.