Triaxial shape of the one-proton emitter ¹⁴⁹Lu

We revisit the proton emitter ¹⁴⁹Lu 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 ¹⁴⁹Lu within experimental uncertainties. A triaxial ground state characterized by (β=0.17,γ=31^∘) has been clarified for ¹⁴⁹Lu. 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 ¹⁴⁹Lu is achieved after considering triaxial deformation degrees of freedom. The examination of the dependence of the decay width on triaxial deformation parameters highlights the significance of microscopic description of nuclear deformation beyond the proton dripline.