Uncertainty-quantified optical potentials for the fission fragment region

Fission fragments present a messy but unique source of experimental data about the many-body physics of neutron-rich nuclei, which has implications in astrophysical nucleosynthesis, energy, and nuclear non-proliferation applications. Currently, phenomenological optical potentials, the nucleon-nucleus interactions used in nuclear reaction models, are calibrated to direct reaction experiments on stable targets, and extrapolated away from stability for applications involving neutron-rich nuclei - including in fission event generators that use Hauser-Feshbach fragment de-excitation, such as CGMF, FIFRELIN, GEF, and Meitner. The goal of this work is to outline the inclusion of compound-nuclear observables - with fission as a case study - into the calibration of these optical potentials, using a Monte Carlo Hauser-Feshbach approach. To make this model calibration computationally tractable, while preserving event-by-event correlations in observables, an intrusive model order reduction technique for calculating transition matrices is constructed using the reduced basis method, with preliminary results showing a speedup on the order of 10^3. Initial results indicate the presence of hitherto untapped constrains on optical potentials in neutron-fragment correlated fission experiments, especially neutron energy spectra as a function of fragment mass and TKE. The overarching goal is to construct the world's first uncertainty-quantified optical potential for the fission fragment region that is simultaneously calibrated to direct reactions on isotopes in this region, as well as experimental fission observables.