alpha-nucleus potentials, alpha-decay half-lives, and shell closures for superheavy nuclei

Systematic alpha-nucleus folding potentials are used to analyze alpha-decay half-lives of superheavy nuclei. Preformation factors of about several per cent are found for all nuclei under study. The systematic behavior of the preformation factors and the volume integrals of the potentials allows to predict alpha-decay energies and half-lives for unknown nuclei. Shell closures can be determined from measured alpha-decay energies using the discontinuity of the volume integral at shell closures. For the first time a double shell closure is predicted for Z_magic = 132, N_magic = 194, and A_magic = 326 from the systematics of folding potentials. The calculated alpha-decay half-lives remain far below one nanosecond for superheavy nuclei with double shell closure and masses above A > 300 independent of the precise knowledge of the magic proton and neutron numbers.