Systematic Study of Fusion Reactions Leading to Superheavy Nuclei

Key words: 
• superheavy nuclei /
• fusion /
• fission /
• quasi-fission /
• shell correction

Abstract: The fusion probability in “hot” fusion reactions leading to the synthesis of superheavy nuclei is investigated systematically. The quasi-fission barrier influences the formation of the superheavy nucleus around the “island of stability” in addition to the shell correction. Based on the quasi-fission barrier height obtained with the Skyrme energy-density functional, we propose an analytical expression for the description of the fusion probability, with which the measured evaporation residual cross sections can be reproduced acceptably well. Simultaneously, some special fusion reactions for synthesizing new elements 119 and 120 are studied. The predicted evaporation residual cross sections for ⁵⁰Ti+²⁴⁹Bk are about 35 fb at energies around the entrance-channel Coulomb barrier. For the fusion reactions synthesizing element 120
with projectiles 54Cr and 58Fe, the cross sections fall to a few femtobarns which seems beyond the limit of the available facilities.