# Diabatic scission paths

## TL;DR

This paper models nuclear fission at the scission point using self-consistent mean-field theory with new path-finding methods to understand the dynamics and energy distribution of fission fragments.

## Contribution

It introduces a novel approach to construct smooth scission paths using Hartree-Fock configurations with K-partition constraints, improving understanding of the fission process.

## Key findings

- Identifies paths with large overlaps between configurations.
- Detects sticking points with significant wave function changes.
- Tracks excitation energy in fission fragments to test statistical models.

## Abstract

An outstanding problem in the theory of nuclear fission is to understand the Hamiltonian dynamics at the scission point. In this work the fissioning nucleus is modeled in self-consistent mean-field theory as a set of Generator Coordinate (GCM) configurations passing through the scission point. In contrast to previous methods, the configurations are constructed in the Hartree-Fock approximation with axially symmetric mean fields and using the K-partition numbers as additional constraints. The goal of this work is to find paths through the scission point where the overlaps between neighboring configurations are large. A measure of distance along the path is proposed that is insensitive to the division of the path into short segments. For most of the tested K-partitions two shape degrees of freedom are adequate to define smooth paths. However, some of the configurations and candidate paths have sticking points where there are substantial changes in the many-body wave function, especially if quasiparticle excitations are present. The excitation energy deposited in fission fragments arising from thermal excitations in the pre-scission configurations is determined by tracking orbital occupation numbers along the scission paths. This allows us to assess the validity of the well-known scission-point statistical model, in which the scission process is assumed to be fully equilibrated up to the separated fission fragments. The nucleus 236U is taken as a representative example in the calculations.