Extension of the Periodic System: Superheavy, Superneutronic, Superstrange, Antimatter Nuclei

The possibilities for the extension of the periodic system into the islands of superheavy (SH) elements, to and beyond the neutron drip line and to the sectors of strangeness and antimatter are discussed in the paper. The multi-nucleon transfer processes in low-energy damped collisions of heavy actinide nuclei may help us to fill the gap between the nuclei produced in the “hot” fusion reactions and the continent of known nuclei. In these reactions we may also investigate the “island of stability”. In many such collisions the lifetime of the composite giant system consisting of two touching nuclei turns out to be rather long (≥10−20 s); sufficient for observing line structure in spontaneous positron emission from super-strong electric fields (vacuum decay), a fundamental QED process not observed yet experimentally. A tremendously rich scenario of new nuclear structure emerges with new magic numbers in the strangeness domain. Various production mechanisms are discussed for these objects and for antinuclei in high energy heavy-ion collisions.