Research program of superheavy elements and nuclides based on HIAF

Abstract

Atomic nuclei are many-body quantum systems composed of protons and neutrons. The nuclides, whose existence is attributed to the nuclear shell effects, are referred to as superheavy nuclides. The exploration of the limit to the existence of nuclides with regard to the proton and mass numbers is at the frontier of nuclear physics research. So far, superheavy elements with an atomic number of up to 118 and hundreds of superheavy nuclides have been experimentally synthesized and identified in various laboratories, resulting in the completion of the seventh period of the periodic table of elements. The High Intensity heavy-ion Accelerator Facility (HIAF) is now under construction and is scheduled to be commissioned in 2025. The study on superheavy elements and nuclei is one of the main research goals of HIAF. Intense heavy-ion beams can be extracted from around the middle point of linac, and the beam energies can be finely adjusted around the Coulomb barriers of nuclear reactions. Therefore, HIAF will provide great opportunities for the synthesis of new superheavy elements and to explore the superheavy island of stability, which was theoretically predicted long ago via fusion and multi-nucleon transfer reactions, respectively. This paper presents the research program of superheavy elements and nuclides based on HIAF, provides an overview of the research on superheavy nuclei, and describes the electromagnetic spectrometers and experimental measurement systems associated with fusion and multi-nucleon transfer reactions. The HIAF physics goals, including the synthesis of new superheavy elements and nuclides, the study on the nuclear structure of superheavy nuclei, the reaction mechanism of producing superheavy nuclides, and the atomic structure and chemical properties of the heaviest elements, are illustrated in detail. Lastly, the future research plan for superheavy elements and nuclides is summarized.