The cross sections of fusion-evaporation reactions: the most promising route to superheavy elements beyond Z=118

¹ Helmholtz Institute Mainz, 55099 Mainz, Germany
² GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany

^* e-mail: J.Khuyagbaatar@gsi.de

Published online: 22 November 2017

Abstract

The synthesis of superheavy elements beyond oganesson (Og), which has atomic number Z = 118, is currently one of the main topics in nuclear physics. An absence of sufficient amounts of target material with atomic numbers heavier than californium (Z = 98) forces the use of projectiles heavier than ⁴⁸Ca (Z = 20), which has been successfully used for the discoveries of elements with Z = 114 - 118 in complete fusion reactions. Experimental cross sections of ⁴⁸Ca with actinide targets behave very differently to “cold” and “hot” fusion-evaporation reactions, where doubly-magic lead and deformed actinides are used as targets, respectively. The known cross sections of these reactions have been analysed compared to calculated fission barriers. It has been suggested that observed discrepancies between the cross sections of ⁴⁸Ca-induced and other fusionevaporation reactions originate from the shell structure of the compound nucleus, which lies in the island of the stability. Besides scarcely known data on other reactions involving heavier projectiles, the most promising projectile for the synthesis of the elements beyond Og seems to be ⁵⁰Ti. However, detailed studies of ⁵⁰Ti, ⁵⁴Cr, ⁵⁸Fe and ⁶⁴Ni-induced reactions are necessary to be performed in order to fully understand the complexities of superheavy element formation.