Study of Reaction Mechanisms for the Synthesis of Super-Heavy Elements

by Hope Donglo, 2d year PhD student at GANIL

The so-called superheavy elements are nuclei with atomic charges (Z) greater than 100. They are predicted to be centred around Z = 114-126 and the neutron numbers (N) = 172-184 known as ”the island of stability” [1] because of extra stability due to the quantum shell effect [2, 3]. Since their predictions, experimental and theoretical efforts have been devoted towards their discovery primarily through the fusion-evaporation reaction mechanism [4].

The synthesis of superheavy elements is a difficult experimental challenge because their cross- section decreases with increasing atomic charge. Furthermore, there are limited projectile- target combinations that can be used in this reaction. Hence, there are theoretical simula- tions to guide the experiments. The theoretical formalism considered the reaction to be a three-stage process, namely, capture, formation, and survival [5]. The formation is an ill- defined step due to the lack of consensus on its modelling. In this presentation, I report on the progress made in incorporating the formation probability within the fusion-by-diffusion formalism into our Kewpie2 code and the approach towards constraining this factor.

References
[1] J. Hong, G. Adamian, N. Antonenko, P. Jachimowicz, and M. Kowal, Physics Letters B 809, 135760 (2020).
[2] D. Boilley, Y. Abe, B. Cauchois, and C. Shen, Journal of Physics G: Nuclear and Particle Physics 46, 115102 (2019).
[3] Y. Abe, G. Kosenko, C. Shen, B. Bouriquet, A. Marchix, D. Boilley, and B. Giraud, Physics of Atomic Nuclei 69, 1101 (2006).
[4] S. Hofmann, Reports on Progress in Physics 61, 639 (1998).
[5] W. Swiatecki,  K.  Siwek-Wilczyn´ska,  and  J.  Wilczyn´ski,  Physical  Review  C  71,  014602 (2005).