📝 SummarXiv

Abstract

In nuclear fission, a heavy nucleus splits into two fragments, driven by the Coulomb repulsion between the positively charged protons. The fission process is governed by the potential energy and basic transport properties of nuclear matter like inertial mass and viscosity. While inertia induces features of memory, viscosity attenuates these features by damping. Exploring signatures of memory in fission is crucial for overcoming the current severe lack of experimental information on the transport properties of nuclear matter. Based on an analysis of hitherto unexplained anomalies in fission-fragment yields and total kinetic energies, we show that the memory of the conditions near the second barrier in the mass-asymmetry degree of freedom is preserved until scission. Our results are in severe conflict with the widely used assumption that the role of collective inertia in fission dynamics is negligible. They therefore falsify the validity of approaches disregarding the influence of inertia, in particular the use of the Smoluchowski equationi in fission modeling. Concomitantly, our work reveals that the widespread assumption of local statistical equilibrium in all collective degrees of freedom along the fission path, which is the foundation of the scission-point model, is violated.