Fusion hindrance in heavy systems with time-dependent Hartree-Fock

Kouhei Washiyama,E.C Simpson,I.P Carter,C Simenel,K.J Cook

doi:10.1051/epjconf/201716300064

Abstract

We analyze fusion hindrance in heavy systems, where the fusion probability around the Coulomb barrier is hindered compared with that in light and medium-mass systems. We perform simulations of central collisions around the Coulomb barrier in heavy systems with time-dependent Hartree‒Fock (TDHF) and find that the fusion hindrance is realized in TDHF simulations. We extract nucleus‒nucleus potential and energy dissipation in heavy systems by a method combining a microscopic TDHF evolution to a macroscopic collective equation of motion. We find that the extracted potentials exhibit a dynamical increase at small relative distances, while the extracted friction coefficients show rather a behavior similar to that in light and medium-mass systems. We find from our analysis that the dynamical increase in potential is a main contribution to this fusion hindrance.

Highlights

The synthesis of superheavy elements by using heavyion fusion reactions has been a major subject in nuclear physics
We briefly explain our method of extracting nucleus–nucleus potential and friction coefficient from time-dependent Hartree–Fock (TDHF) simulations, which consists of the following steps: i) First, we perform TDHF simulations for central collisions to obtain the time evolution of densities of a colliding system. ii) From the obtained densities, we divide the colliding system into projectile-like and target-like fragments by properly defining a neck position
We performed the analysis of the fusion hindrance by using TDHF dynamics

Summary

Introduction

The synthesis of superheavy elements by using heavyion fusion reactions has been a major subject in nuclear physics. The discovery of superheavy elements gives an impact in our society. In Japan, a great impact has been given to a wide area of Japanese society through major newspapers and TV news since Nihonium was discovered and named. The discovery of such superheavy elements has been realized by a recent progress on experimental technique in heavy-ion fusion reactions. Lack of understanding the whole process of superheavy element synthesis that is from the entrance channel to survival of evaporation residue against fission. Lack of understanding the whole process of superheavy element synthesis that is from the entrance channel to survival of evaporation residue against fission. is still significant

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Conclusion