Evidence for α clustering in heavy and superheavy nuclei -: art. no. 044318

We analyze the alpha decay between ground states along N-Z chains in deformed heavy and superheavy nuclei, by using the pairing approach. We show that the derivative of the preformation amplitude is practically a constant along any alpha chain, while that of the outgoing wave function changes exponentially upon the Coulomb parameter. This leads to the breakdown of the continuity equation and therefore to wrong decay widths. The behavior cannot be explained within the standard shell model. We significantly correct this deficiency by considering an alpha-cluster factor in the preformation amplitude, depending exponentially upon the Coulomb parameter. Thus, four-body correlations, connected with the radial shape of the preformation factor, are directly evidenced by the alpha-decay systematics. Moreover, this procedure, in principle, fully determines the Q value and is an important development in the alpha-decay theory. It also allows us to analyze the relative alpha-clustering structure of the emitter. It turns out that the isotopes close to the region N>126 and superheavy nuclei have a stronger clustering behavior. For superheavy region an additional dependence upon the number of interacting alpha particles is necessary.