Spatial orientation of the fission fragment intrinsic spins and their correlations

Abstract

New experimental and theoretical results obtained in 2021 made it acutely clear that more than 80 years after the discovery of nuclear fission we do not understand the generation and dynamics of fission fragment (FF) intrinsic spins well, in particular their magnitudes, their spatial orientation, and their correlations. The magnitude and orientation of the primary FFs have a crucial role in defining the angular distribution and correlation between the emitted prompt neutrons, and subsequent emission of statistical (predominantly E1) and stretched E2 γ-rays, and their correlations with the final fission fragments. Here we present detailed microscopic evaluations of the FF intrinsic spins, for both even- and odd-mass FFs, and of their spatial correlations. These point to a well-defined 3D FF intrinsic spin dynamics, characteristics absent in semi-phenomenological studies, due to the presence of the twisting spin modes, which artificially were suppressed in semi-phenomenological studies.

arXiv comment4 pages, 3 figures

References in corpus (24)

• Induced Fission of ${}^{240}$Pu within a Real-Time Microscopic Framework
• Efficient numerical computation of the Pfaffian for dense and banded skew-symmetric matrices
• The sign of the overlap of HFB wave functions
• Fission Dynamics of 240Pu from Saddle-to-Scission and Beyond
• Calculation of fission observables through event-by-event simulation
• Symmetry restoration in Hartree-Fock-Bogoliubov based theories
• A Minimal Nuclear Energy Density Functional
• Nuclear Fission Dynamics: Past, Present, Needs, and Future
• Generation of fragment angular momentum in fission
• Projection on particle number and angular momentum: Example of triaxial Bogoliubov quasiparticle states
• Fission fragments intrinsic spins and their correlations
• Event-by-event study of prompt neutrons from 239Pu(n,f)
• Angular Momentum of Fission Fragments from Microscopic Theory
• Study of angular momentum effects in fission
• Measures of complexity and entanglement in fermionic many-body systems
• Unitary evolution with fluctuations and dissipation
• Entanglement entropy, single-particle occupation probabilities, and short-range correlations
• The angular correlation between the fission fragment intrinsic spins
• Coupled fission fragment angular momenta
• Generation, dynamics, and correlations of the fission fragments' angular momenta
• Pairing dynamics and solitonic excitations in collisions of medium-mass, identical nuclei
• Pure quantum extension of the semiclassical Boltzmann-Uehling-Uhlenbeck equation
• Microscopic description of the torque acting on fission fragments
• New developments in fission studies within the time-dependent density functional theory framework

Cited by in corpus (7)

• Nuclear Quantum Many-Body Dynamics: From Collective Vibrations to Heavy-Ion Collisions (2nd edition)
• Microscopic Study of Spin Transfer in Near-Barrier Nuclear Reactions
• Non-Markovian character and irreversibility of real-time quantum many-body dynamics
• Time-Dependent Density Functional Theory Description of ${}^{238}$U(n,f), ${}^{240,242}$Pu(n,f) and ${}^{237}$Np(n,f) Reactions
• Quantum-mechanical description of angular motion of fission fragments at scission
• Microscopic theory of angular momentum distributions across the full range of fission fragments
• A critical assessment of the current implementations of the Generator Coordinate Method