Seminar “Nuclear Theory”

Date and Time: Monday, 1 March 2021, at 3:30 PM

Venue: Online conference on Zoom, Bogoliubov Laboratory of Theoretical Physics

Seminar topic: «Development of the quantum theory of low-energy binary and ternary nuclear fission by cold polarized neutrons»

Speaker: D. E. Lubashevsky (Voronezh State University)

Abstract:

The widely used traditional fission theories are largely macroscopic in nature, which is related to the hydrodynamic (a nuclear drop model with shell corrections) and thermodynamic (Gibbs distribution, Langevin equations) characteristics of fissioning nuclei, and in a sense have no consistent quantum mechanical background. That is why the subject of the dissertation related to the study of important but poorly known properties of low-energy binary and ternary nuclear fission in the framework of the quantum theory seems to be relevant.
Along with the development of new theoretical concepts, we have confirmed the existence of a new class of multistage nuclear reactions and decays associated with the appearance of virtual states of intermediate nuclei. In addition, the experimental characteristics of 2p and 2β decays of nuclei were described, and evidence of the virtual nature of ternary nuclear fission with the emission of prescission α particles was obtained.
The appearance of large values of the relative orbital momenta of fragments of low-energy binary nuclear fission was explained by taking into account the influence of transverse wriggling nuclear vibrations. It was shown that the spin distributions of excited fragments of double nuclear fission at low energies are nonequilibrium. A unified mechanism for the formation of ternary and quintuple P-even T-odd scalar correlations in the differential cross sections of ternary nuclear fission by cold polarized neutrons with the emission of prescission α- particles, as well as prompt neutrons and gamma quanta were substantiated.

(based on Dr.Sc. Thesis)