Three-Body Barrier Dynamics of Double-Alpha Decay in Heavy Nuclei
Abstract
The simultaneous emission of two α particles--double-α decay--represents a long-predicted but unobserved mode of nuclear radioactivity. Here we formulate this process as a genuine three-body problem within the hyperspherical coordinate framework and evaluate decay probabilities by numerically solving the corresponding hyperradial Schr\"odinger equation, combined with large-scale random sampling of the potential parameters; the latter treatment ensures that the present results are more convincing. Inspired by this, we demonstrate that the penetrability ratio between simultaneous and sequential α emission exhibits a strikingly linear dependence on ZQαα-1/2, extending the barrier penetration dynamics into the correlated few-body regime. The nuclei 108Xe, 218Ra, 224Pu, 222U, 216Rn, and 220Th are suggested as the most promising candidates for the observation of double-α decay, with predicted half-lives potentially accessible within present detection limits. Our results provide a unified framework for multi-α decay and open a pathway to probing nuclear clustering and few-body correlations in heavy nuclei.