How the Pauli exclusion principle affects fusion of atomic nuclei

TL;DR

This paper investigates how the Pauli exclusion principle causes repulsion between colliding atomic nuclei, affecting fusion probabilities, and introduces a new microscopic method to accurately compute this effect, addressing the deep sub-barrier fusion hindrance.

Contribution

It presents a novel density-constrained frozen Hartree-Fock approach to precisely include Pauli repulsion in fusion potential calculations.

Findings

Pauli repulsion increases with nuclear charge product.

It significantly reduces tunnelling probability.

It helps explain deep sub-barrier fusion hindrance.

Abstract

The Pauli exclusion principle induces a repulsion between composite systems of identical fermions such as colliding atomic nuclei. Our goal is to study how heavy-ion fusion is impacted by this "Pauli repulsion". We propose a new microscopic approach, the density-constrained frozen Hartree-Fock method, to compute the bare potential including the Pauli exclusion principle exactly. Pauli repulsion is shown to be important inside the barrier radius and increases with the charge product of the nuclei. Its main effect is to reduce tunnelling probability. Pauli repulsion is part of the solution to the long-standing deep sub-barrier fusion hindrance problem.