Statistical and dynamical aspects in fission process: The rotational degrees of freedom

Abstract

In the final phases of fission process, there are fast collective rotational degrees of freedom, which can exert a force on the slower tilting rotational degree. Experimental observations that lead to this realization and theoretical studies that account for dynamics of the processes are discussed briefly. Supported by these studies, and by assuming a conditional equilibrium of the collective rotational modes at a pre-scission point, a new statistical model for fission fragment angular and spin distributions has been developed. This model gives a consistent description of the fragment angular and spin distributions for a wide variety of heavy- and light-ion-induced fission reactions.