Yi Xu, Dimiter L. Balabanski, Virgil Baran, Cristian Iorga, Catalin Matei [ https://www.sciencedirect.com/science/article/pii/S0370269324001801 ]
The vortex photons (also referred to as twisted or orbital angular momentum [OAM] photons), open new research avenues across several scientific fields. However, their application in nuclear physics research has not been studied in depth. In the present study, we have demonstrated the perspectives for the nuclear physic studies with the OAM photons.
At first, the interaction formalism of nuclei with vortex photons is developed and incorporated into the statistical nuclear reaction model. Using this model, the cross-sections of γ-ray emission and neutron production from the decay of the giant resonances (GR) populated by vortex photons are computed for 138 nuclei of high nuclear astrophysics and structure interest. It is shown in that for the cross-sections of both gamma-ray emission and neutron production, the GR contribution of a specific multipolarity L is either enhanced or suppressed depending on the parameters of the vortex photons, and the contribution from such GR can be then identified and deduced. As an example, the γ-ray emission cross-sections with the vortex photon parameters mγ = 1 and mγ = 2 are presented, and the ratios of their differences to the results of mγ = 1 are illustrated in the Figure for the vortex-photon energy of 6 MeV.
Based on the theoretical results, a novel method to exclusively determine the photon strength function (PSF) for the GR of a specific multipolarity is proposed considering the measurements of γ-ray emission and neutron production. The feasibility studies demonstrate that the PSF for the giant quadrupole resonance can be readily extracted.
Furthermore, the astrophysical reaction rates of the vortex-photon induced reactions in the p-process are investigated, which indicates that the reaction rates can be enhanced by a factor of 2-5 according to different vortex photon parameters.
In summary, it is indicated that photo-nuclear reactions induced by vortex photons will bring new insights in nuclear physics and astrophysics research.
This theoretical study, which is first of its kind, was conducted by a team of experts from the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) - Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH) and the Faculty of Physics, University of Bucharest. It was initiated by scientists from the Gamma Driven Experiments Department (GDED) at ELI-NP, and the input of the colleagues from the University of Bucharest was crucial for solving the problem. It is a follow-up research of the PNCDI III project "Frontiers Research in Photon-Matter Interaction Using Extreme Helical Light Beams" with the Romanian Research Fund (PN-III-P4-ID-PPCF-2016-0164).
