Proton radioactivity in deformed nuclei with microscopic optical potential: a novel angular-dependent emission mechanism in the nanosecond-emitter ¹⁴⁹Lu

We present the first microscopic description of proton radioactivity in ¹⁴⁹Lu, the most oblate deformed proton emitter known, using a deformed microscopic optical potential derived from $ab\ initio$ nuclear matter calculations. We predict a novel angular-dependent phenomenon unprecedented in spherical proton emitters: the disappearance of classically allowed regions at small polar angles (θ≤ 21^∘). Combining the Wentzel-Kramers-Brillouin penetration probabilities and the assault frequency of the emitted proton estimated with a new harmonic-oscillator-inspired scheme, our framework yields a half-life T1/2=467⁺¹⁴³₋₁₀₈ ns for ¹⁴⁹Lu, in excellent agreement within uncertainties with the experimental value 450⁺¹⁷⁰₋₁₀₀ ns. Deformation analysis rigorously excludes configurations with |β₂|≥ 0.32. Extensions to 150, 151Lu and their isomers also achieve excellent agreement with experimental half-life data. We further predict ¹⁴⁸Lu as another highly oblate (β₂ = -0.166) proton emitter with a half-life of 4.42 ns. This work validates deformed microscopic optical potentials as a robust predictive tool for drip-line proton emitters and provides quantitative evidence for deformation effects in exotic decays.