Structure of $^{128,129,130}$Xe through multi-reference energy density functional calculations

TL;DR

This study uses advanced energy density functional calculations to analyze the triaxial shapes of xenon isotopes $^{128,129,130}$Xe, successfully reproducing low-energy spectra and revealing pronounced triaxial ground states.

Contribution

The paper introduces multi-reference energy density functional calculations incorporating shape mixing and symmetry restoration for xenon isotopes, highlighting their triaxial ground states.

Findings

All three isotopes exhibit pronounced triaxial ground states.

Calculations reproduce low-energy spectra of $^{128}$ and $^{130}$Xe.

Some discrepancies are observed in the $^{129}$Xe results.

Abstract

Recently, values for the Kumar quadrupole deformation parameters of the nucleus $^{130}$Xe have been computed from the results of a Coulomb excitation experiment, indicating that this xenon isotope has a prominent triaxial ground state. Within a different context, it was recently argued that the analysis of particle correlations in the final states of ultra-relativistic heavy-ion collisions performed at the Large Hadron Collider (LHC) points to a similar structure for the adjacent isotope, $^{129}$Xe. In the present work, we report on state-of-the-art multi-reference energy density functional calculations that combine projection on proton and neutron number as well as angular momentum with shape mixing for the three isotopes $^{128,129,130}$Xe using the Skyrme-type pseudo-potential SLyMR1. Exploring the triaxial degree of freedom, we demonstrate that the ground states of all three isotopes display a very pronounced triaxial structure. Moreover, comparison with experimental results shows that the calculations reproduce fairly well the low-energy excitation spectrum of the two even-mass isotopes. By contrast, the calculation of $^{129}$Xe reveals some deficiencies of the effective interaction.