Spontaneous fission modes and lifetimes of super-heavy elements in the nuclear density functional theory

TL;DR

This study uses advanced nuclear density functional theory to analyze spontaneous fission modes and lifetimes of super-heavy elements, predicting decay behaviors and identifying regions of stability and instability among these nuclei.

Contribution

It introduces a comprehensive theoretical framework that accounts for symmetry breaking and competing fission modes to predict lifetimes and decay pathways of super-heavy nuclei.

Findings

Short-lived isotopes are in a narrow decay corridor.

Two competing fission modes identified: symmetric and asymmetric.

Long-lived nuclei are centered around $^{294}$Ds with ~1.5 days half-life.

Abstract

Lifetimes of super-heavy (SH) nuclei are primarily governed by alpha decay and spontaneous fission (SF). Here we study the competing decay modes of even-even SH isotopes with 108 <= Z <= 126 and 148 <= N <= 188 using the state-of-the-art self-consistent nuclear density functional theory framework capable of describing the competition between nuclear attraction and electrostatic repulsion. The collective mass tensor of the fissioning superfluid nucleus is computed by means of the cranking approximation to the adiabatic time-dependent Hartree-Fock-Bogoliubov approach. Along the path to fission, our calculations allow for the simultaneous breaking of axial and space inversion symmetries; this may result in lowering SF lifetimes by more than seven orders of magnitude in some cases. We predict two competing SF modes: reflection-symmetric and reflection-asymmetric.The shortest-lived SH isotopes decay by SF; they are expected to lie in a narrow corridor formed by $^{280}$Hs, $^{284}$Fl, and $^{284}_{118}$Uuo that separates the regions of SH nuclei synthesized in "cold fusion" and "hot fusion" reactions. The region of long-lived SH nuclei is expected to be centered on $^{294}$Ds with a total half-life of ?1.5 days.