Future of superheavy element research: Which nuclei could be synthesized within the next few years?

TL;DR

This paper explores various nuclear reactions, including fusion, transfer, and neutron capture, to synthesize new superheavy elements, highlighting feasible pathways and experimental prospects within the next few years.

Contribution

It identifies new potential reaction pathways, especially involving $^{48}$Ca and beta decay, to produce superheavy nuclei near the island of stability.

Findings

Fusion of $^{48}$Ca with lighter isotopes can produce nuclei with sizable cross sections.

Multi-nucleon transfer reactions are promising for creating neutron-rich heavy nuclei.

Neutron capture reactions could generate long-lived superheavy isotopes.

Abstract

Low values of the fusion cross sections and very short half-lives of nuclei with Z$>$120 put obstacles in synthesis of new elements. Different nuclear reactions (fusion of stable and radioactive nuclei, multi-nucleon transfers and neutron capture), which could be used for the production of new isotopes of superheavy (SH) elements, are discussed in the paper. The gap of unknown SH nuclei, located between the isotopes which were produced earlier in the cold and hot fusion reactions, can be filled in fusion reactions of $^{48}$Ca with available lighter isotopes of Pu, Am, and Cm. Cross sections for the production of these nuclei are predicted to be rather large, and the corresponding experiments can be easily performed at existing facilities. For the first time, a narrow pathway is found to the middle of the island of stability owing to possible $\beta^+$-decay of SH isotopes which can be formed in ordinary fusion reactions of stable nuclei. Multi-nucleon transfer processes at near barrier collisions of heavy (and very heavy, U-like) ions are shown to be quite realistic reaction mechanism allowing us to produce new neutron enriched heavy nuclei located in the unexplored upper part of the nuclear map. Neutron capture reactions can be also used for the production of the long-living neutron rich SH nuclei. Strong neutron fluxes might be provided by pulsed nuclear reactors and by nuclear explosions in laboratory conditions and by supernova explosions in nature. All these possibilities are discussed in the paper.