In the realm of nuclear physics, a team of researchers from the University of Washington, including Ibrahim Abdurrahman, Andrzej Makowski, Guillaume Scamps, Kyle Godbey, and Piotr Magierski, has been delving into the intricate dynamics of nuclear reactions. Their recent work, published in the journal Physical Review C, focuses on the role of pairing correlations in neutron transfer during sub-barrier fusion reactions, specifically in collisions involving calcium-40, calcium-48, and zirconium-96 nuclei.
Sub-barrier fusion reactions occur when two nuclei collide with energies below the Coulomb barrier, the energy threshold typically required for fusion to occur. These reactions are particularly useful for studying the effects of pairing correlations, which describe how nucleons (protons and neutrons) interact and form pairs within the nucleus. Previous studies using the Bardeen-Cooper-Schrieffer (BCS) approximation, a method used to describe superconductivity and superfluidity in nuclear systems, showed that pairing correlations enhance neutron transfer. However, these studies fell short of explaining the observed enhancement factor between one- and two-neutron transfer probabilities.
To address this gap, the researchers employed time-dependent energy density functional theory extended to superfluid systems, known as TDSLDA. This microscopic approach allows for a detailed investigation of the dynamics of head-on collisions between calcium-40/calcium-48 and zirconium-96 nuclei below the Coulomb barrier. By using projection operators, the team extracted transfer probabilities, including contributions to specific angular momentum projections, and compared these results to calculations without pairing.
The findings revealed that pairing correlations are strongly linked to the dynamic deformability of the nucleus, which in turn influences mean neutron transfer in sub-barrier reactions. Notably, the TDSLDA calculations successfully reproduced the experimentally observed enhancement factor by significantly increasing the probability of transferring a neutron pair in the spin channel where the angular momentum projection is zero (K = 0). This result underscores the strong influence of pairing and nuclear structure on sub-barrier multi-nucleon transfer.
The practical implications of this research for the energy sector, particularly nuclear energy, are significant. A deeper understanding of nuclear reactions and the role of pairing correlations can contribute to the development of advanced nuclear fuels and more efficient reactor designs. By improving our knowledge of neutron transfer processes, researchers can enhance the safety and efficiency of nuclear power generation, a critical component of the global energy mix.
The research was published in Physical Review C, a peer-reviewed journal dedicated to the publication of significant advances in the understanding of nuclear structure and nuclear reactions. This study represents a step forward in the microscopic description of nuclear dynamics, providing a reliable framework for future investigations into the interplay between nuclear superfluidity and reaction dynamics.
This article is based on research available at arXiv.