Role of hexadecapole deformation of projectile ${}^{28}$Si in heavy-ion fusion reactions near the Coulomb barrier

Abstract

The vast knowledge of strong influence of quadrupole deformation ${\hat{I}}_2^2$ of colliding nuclei on heavy-ion subbarrier fusion reactions inspires a desire to quest the sensitivity of fusion dynamics to higher order deformations, such as ${\hat{I}}_4^2$ and ${\hat{I}}_6^2$ deformations. However, such studies have rarely been carried out, especially for deformation of projectile nuclei. In this article, we investigated the role of ${\hat{I}}_4^2$ of the projectile nucleus in fusion of the ${}^{28}$Si + ${}^{92}$Zr system. We demonstrated that the fusion barrier distribution is sensitive to the sign and the value of the ${\hat{I}}_4^2$ parameter of the projectile, ${}^{28}$Si, and confirmed that the ${}^{28}$Si nucleus has a large positive ${\hat{I}}_4^2$. This study opens an indirect way to estimate deformation parameters of radioactive nuclei using fusion reactions, which is otherwise difficult due to experimental constraints.