Mapping of Enhanced Nuclear Stability in the Heaviest Elements

Abstract

Predictions of the properties of nuclides near the extreme limits of nuclear stability provide a measure of our understanding of the fundamental properties of matter and the fission process. Predictions of an ''island of stability'' of long-lived superheavy elements beyond the limits of the known nuclides date back more than 30 years; during this time, there have been many unsuccessful searches for these nuclei. During the last decade, there has been a large effort by our group and others to systematically discover and characterize the properties of the intervening unstable nuclei. Starting 10 years ago, in an on-going collaboration with Russian scientists at the Joint Institute for Nuclear Research (JINR) at Dubna, Russia, we observed the decays of previously unknown isotopes of elements 106, 108, and 110 whose properties are determined by subtleties in the nuclear structure caused by the shell effects that are predicted to result in the island of stability in the still-heavier elements. The resulting data have been successfully reproduced by the theoreticians, whose refined predictions of the decay modes and production rates of the superheavy elements have enabled us to design experiments with the sensitivity to locate these elusive nuclides.