Decay modes and a limit of existence of nuclei

Koura, Hiroyuki   

Nucleus is a composite system consisting of protons and neutrons, and approximately 3000 nuclides have been identified experimentally. However, the existence of much more nuclides is postulated theoretically. How far the area of nuclei extends is an important question in nuclear physics. We have developed an original model based on the macroscopic and mean-field models to describe nuclear masses, called the KTUY (Koura-Tachibana-Uno-Yamada) mass model. By using the KTUY model, we have studied decay modes for alpha-decay, beta-decay, proton emission and spontaneous fission in the wide nuclear mass region. In the extremely heavier nuclear mass region, a large amount of nuclei located over is predicted to exist. This region of nuclei with longer lives than 1ns ends or is disconnected at . The total number of nuclei having more than 1 ns is estimated to be ten thousands. If we focus on half-lives of 1 ms or longer, number of nuclei would be roughly eight thousands.