2025/12/12 by Randrup, Jorgen, Nadtochy, Pavel, Schmitt, Christelle +1
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Cold Fusion and Nuclear Reactions #FOS: Physical sciences #Nuclear Theory (nucl-th) #Nuclear physics research studies #Nuclear reactor physics and engineering
paper · doi:10.48550/arxiv.2512.11212
openalex publication_date 2025/12/12 · openalex created_date 2025/12/16 · openalex updated_date 2026/07/28
This study explores the role of nucleon exchange for the generation of the fission fragment angular momenta. For a number of typical fission cases, samples of 10,000 shape evolutions are generated by Langevin simulation and, subsequently, for each such evolution, the nucleon exchange transport theory previously developed for damped nuclear reactions is used to obtain the development of the fragment spin-spin distribution within the Fokker-Planck transport framework. The characteristic evolution of both parallel and perpendicular spin components is discussed. A common feature is that the rotational modes fall out of equilibrium before scission when the temperature rises rapidly while the concurrent shrinking of the neck suppresses further exchange. A number of fission observables are extracted from the event ensembles: the distribution of the magnitude of the fragment spin and its orientation relative to the fission axis, as well as the correlation between the two spins and the distribution of their opening angle. The dependence of these observables on the mass asymmetry is also examined.