Simultaneous $\alpha \beta$ Decay: A New Mode of Nuclear Instability

Abstract

We propose simultaneous $\alpha \beta$ decay as a novel mode of nuclear instability that involves the strong and weak interactions in a single quantum transition. We develop a theoretical framework to predict its branching ratios and $\alpha$-energy spectra, establishing exclusive and inclusive criteria based on whether the individual $\alpha$ and $\beta$ channels are closed or open. A global survey of the nuclear chart identifies five exclusive $\alpha {\beta }^{-}$ candidates, all predicted to be experimentally inaccessible, and ranks the leading inclusive candidates for both the $\alpha {\beta }^{-}$ and $\alpha {\beta }^{+}$ modes. Remarkably, six of the top $\alpha {\beta }^{+}$ candidates coincide with known $\beta$-delayed-$\alpha$ precursors. The observed $\alpha$ spectra are naturally accounted for by simultaneous $\alpha {\beta }^{+}$ emission, suggesting direct decay as the dominant underlying mechanism. Our findings establish simultaneous $\alpha \beta$ decay as a distinct radioactive process and a sensitive probe of the interplay between the strong and weak interactions.

Comments: 6 pages, 2 figures