Quasifission dynamics and stability of superheavy systems

TL;DR

This paper investigates quasifission dynamics in superheavy systems using microscopic TDHF theory, revealing insights into energy dissipation, nucleon transfer, and reaction mechanisms, with results aligning well with experimental data.

Contribution

It applies the TDHF approach systematically to various reactions, providing a detailed understanding of quasifission processes and improving mass variance predictions with the Balian-Vénéroni method.

Findings

TDHF reproduces experimental trends in energy dissipation and nucleon transfer.

Balian-Vénéroni variational principle improves mass variance predictions.

Reaction mechanisms are elucidated, guiding future research.

Abstract

Recent experiments revealed intriguing similarities in the $^{64}$Ni+$^{207}$Pb, $^{132}$Xe+$^{208}$Pb, and $^{238}$U+$^{238}$U reactions at energies around the Coulomb barrier. The experimental data indicate that for all systems substantial energy dissipation takes place, in the first stage of the reaction, although the number of transferred nucleons is small. On the other hand, in the second stage, a large number of nucleons are transferred with small friction and small consumption of time. To understand the observed behavior, various reactions were analyzed based on the microscopic time-dependent Hartree-Fock (TDHF) theory. From a systematic analysis for $^{40,48}$Ca+$^{124}$Sn, $^{40}$Ca+$^{208}$Pb, $^{40}$Ar+$^{208}$Pb, $^{58}$Ni+$^{208}$Pb, $^{64}$Ni+$^{238}$U, $^{136}$Xe+ $^{198}$Pt, and $^{238}$U+$^{238}$U reactions, we find that TDHF reproduces well the measured trends. In addition, the Balian-V\'en\'eroni variational principle is applied to head-on collisions of $^{238}$U+$^{238}$U, and the variance of the fragment masses is compared with the experimental data, showing significant improvement. The underlying reaction mechanisms and possible future studies are discussed.