Organizers: A. Bulgac, J. Randrup, I. Stetcu, and J.N. Wilson
A workshop hosted by the Nuclear Theory Group at the University of Washington in Seattle will be held on the topic of Fission Fragment Angular Momenta between 21st and 24th June 2022. The meeting will be mostly held online between 8.30 am and 11.30 am US/Pacific time to accommodate participation from different time zones and to facilitate discussion on this important topic. There is the possibility for a small number of participants to be physically present.
Overview
Several papers concerning the intrinsic spins of fission fragments have been published recently and they are listed here in the order they appeared either in a journal or on arXiv.
● R. Vogt and J. Randrup, Angular momentum effects in fission, Phys. Rev. C 103, 014610 (2021).
● J. N. Wilson et al., Angular momentum generation in nuclear fission, Nature (London) 590, 566 (2021).
● A. Bulgac, I. Abdurrahman, S. Jin, K. Godbey, N. Schunck, and I. Stetcu, Fission Fragment Intrinsic Spins and Their Correlations, Phys. Rev. Lett. 126, 142502 (2021).
● J. Randrup and R. Vogt, Generation of Fragment Angular Momentum in Fission, Phys. Rev. Lett. 127, 062502 (2021).
● P. Marević, N. Schunck, J. Randrup, and R. Vogt, Angular momentum of fission fragments from microscopic theory, Phys. Rev. C 104, L021601 (2021).
● M. Travar et al., Experimental information on mass-and TKE-dependence of the prompt fissionγ-ray multiplicity, Phys. Lett. B817 136293 (2021)
● A. Bulgac, The angular correlation between the fission fragment intrinsic
spins, arXiv:2108.07268
● I. Stetcu, A. E. Lovell, P. Talou, T. Kawano, S. Marin, S. A. Pozzi, and A. Bulgac, Angular Momentum Removal by Neutron and γ-Ray Emissions During Fission Fragment Decays, Phys. Rev. Lett. 127, 222502 (2021).
● A. Al-Adili, Z. Gao, M. Lantz, A. Solders, M. Osterlund, S. Pomp, Isomer Yields in nuclear fission, EPJ Web Conf. 256, 00002 (2021)
● A. Bulgac, I. Abdurrahman, K. Godbey, I. Stetcu, Fragment Intrinsic Spins and Fragments’Relative Orbital Angular Momentum in Nuclear Fission, Phys. Rev. Lett. 128, 022501 (2022).
The paper by Wilson et al. is an experimental paper, as are those of Travar et al. and Al-Adili et al., while the rest are theoretical studies. They all have in common that they discuss the angular momenta of the fission fragments, though at different stages: before scission, right after scission, before any prompt neutrons or photons have been emitted, and after the prompt neutrons and statistical photons have been emitted. The interpretations in different studies are most of the time at odds with the interpretations in other studies and clearly there are still a lot of crucial questions that are not settled at this time. The distribution of angular momenta in fission fragments is important because it determines the competition between neutron and photon emission during the subsequent relaxation towards the ground states of the product nuclei.
