Brownian shape motion on five-dimensional potential-energy surfaces: Nuclear fission-fragment mass distributions

TL;DR

This paper introduces a Brownian motion-based model for nuclear shape evolution on five-dimensional potential-energy surfaces, achieving accurate predictions of fission fragment mass distributions with minimal parameters.

Contribution

It presents a novel stochastic approach to model nuclear fission fragment yields using Brownian motion on detailed potential-energy surfaces, with only one global parameter.

Findings

Good reproduction of experimental mass yields

Model is insensitive to the critical neck size parameter

Requires only a single global parameter

Abstract

Although nuclear fission can be understood qualitatively as an evolution of the nuclear shape, a quantitative description has proven to be very elusive. In particular, until now, there exists no model with demonstrated predictive power for the fission fragment mass yields. Exploiting the expected strongly damped character of nuclear dynamics, we treat the nuclear shape evolution in analogy with Brownian motion and perform random walks on five-dimensional fission potential-energy surfaces which were calculated previously and are the most comprehensive available. Test applications give good reproduction of highly variable experimental mass yields. This novel general approach requires only a single new global parameter, namely the critical neck size at which the mass split is frozen in, and the results are remarkably insensitive to its specific value.