Triaxial shape of the one-proton emitter $^{149}$Lu

TL;DR

This study uses advanced triaxial relativistic Hartree-Bogoliubov theory to accurately model the structure and proton emission half-life of $^{149}$Lu, highlighting the importance of triaxial deformation in nuclear decay.

Contribution

It introduces the application of triaxial relativistic Hartree-Bogoliubov theory in continuum to proton emitters, providing a more precise description of $^{149}$Lu's structure and decay properties.

Findings

Successfully reproduces the measured half-life of $^{149}$Lu.

Identifies a triaxial ground state with specific deformation parameters.

Shows that triaxiality significantly affects nuclear density and decay predictions.

Abstract

We revisit the proton emitter $^{149}$Lu utilizing the recently developed triaxial relativistic Hartree-Bogoliubov theory in continuum (TRHBc). By incorporating the microscopic nuclear structure properties from the TRHBc theory into the WKB approximation, we successfully reproduce the measured proton-emission half-life of $^{149}$Lu within experimental uncertainties. A triaxial ground state characterized by ($\beta=0.17,\gamma=31^\circ$) has been clarified for $^{149}$Lu. The inclusion of triaxiality significantly changes nuclear density distributions and potentials, which results in enhanced binding of both the nuclear system and the proton-emitting orbital. As a result, a slightly extended half-life for the proton emission of $^{149}$Lu is achieved after considering triaxial deformation degrees of freedom.