Collision dynamics of two $^{238}$U atomic nuclei

TL;DR

This study uses quantum simulations to analyze the collision dynamics of two uranium-238 nuclei, highlighting the effects of nuclear deformation and the potential for observing spontaneous positron-electron pair emission.

Contribution

It provides a microscopic quantum analysis of uranium-238 collisions, emphasizing deformation effects and predicting collision times relevant for experimental detection of quantum electrodynamics phenomena.

Findings

Collision times up to 4×10^{-21} s at 1200 MeV.

Nuclear deformation influences collision duration and transfer mechanisms.

Observation of ternary fission due to dynamical effects.

Abstract

Collisions of actinide nuclei form, during very short times of few $10^{-21}$ s, the heaviest ensembles of interacting nucleons available on Earth. Such very heavy ions collisions have been proposed as an alternative way to produce heavy and superheavy elements. These collisions are also used to produce super-strong electric fields by the huge number of interacting protons to test spontaneous positron-electron ($e^+e^-$) pair emission predicted by the quantum electrodynamics theory. The time-dependent Hartree-Fock theory which is a fully microscopic quantum approach is used to study collision dynamics of two $^{238}$U atomic nuclei. In particular, the role of nuclear deformation on collision time and on reaction mechanisms such as nucleon transfer is emphasized. These calculations are pessimistic in terms of transfermium elements ($Z>100$) production. However, the highest collision times ($\sim4\times10^{-21}$ s at 1200 MeV) should allow experimental signature of spontaneous $e^+e^-$ emission. Surprisingly, we also observe ternary fission due to purely dynamical effects.