Global view on fission observables – new insights and new puzzles

An overview is given on some measurable quantities that carry information on the evolution of the fissioning system from the quasi-bound configuration to the final fission fragments in their respective ground states. New insights into the nature of the fission process, but also new puzzles, emerging from recent experimental findings, are presented. They cover the following topics: Dynamics: Early freeze-out due to dynamical effects; importance of quantum-mechanical effects for fluctuations and angular-momentum pumping.Systematics of fission channels: Separability principle, a powerful application of the macroscopic-microscopic approach to fission; the puzzle of the apparent role of proton shells.Energetics: Transformation of the potential-energy gain into kinetic energy, single-particle excitations, and collective excitations; heat transfer between the nascent fragments; consequences for prompt-neutron emission and the even–odd effect in fragment yields; ambiguities and model dependences.New experimental knowledge on the nuclear level density is included in the discussion.