Lifetimes and moments measurements to investigate the structure of midheavy nuclei

TL;DR

This paper discusses measurements of nuclear lifetimes and electromagnetic moments in mid-heavy nuclei to explore their complex structures, shape coexistence, and octupole collectivity, using gamma spectroscopy data from recent experiments.

Contribution

It presents new lifetime measurements and structural insights into mid-heavy nuclei, especially neutron-rich barium isotopes and hafnium isotopes, advancing understanding of shape phenomena.

Findings

Evidence of octupole degrees of freedom in $^{144-146}$Ba

Preliminary lifetime data on hafnium isotopes

Insights into shape coexistence and evolution

Abstract

Mid-heavy nuclei offer unique opportunities to study the collective and single-particle aspects of nuclear structure. This mass regime is a dynamic area where protons and neutrons generally occupy different orbitals, giving rise to complex structures with a wide variety of shapes, shape evolution and shape coexistence. To that end, measurements of nuclear lifetimes and electromagnetic moments ($\mu$,$Q$) can be invaluable. Recent experimental activities of the NuSTRAP group in Athens have focused on $\gamma$-spectroscopy studies employing the RoSPHERE array in Magurele, Romania. In recent studies [1,2], the neutron-rich $^{144-146}$Ba isotopes have exhibited octupole degrees of freedom. Similar questions exist for the lighter $^{140}$Ba isotope, which is located at the onset of octupole collectivity. In addition, understanding the structure of heavier, even-even hafnium isotopes requires more data regarding shape coexistence and shape evolution. Preliminary results on lifetimes in this area pave the way to understand dynamical phenomena prior to studying more exotic species in the future.