This companion derives and documents the WKB prefactor used in the neutron junction-slip decay rate, including the determinant ratio and normalization conventions (e.g., Gel’fand–Yaglom / fluctuation operator treatment). It is designed as a compact, citable technical note that fixes the prefactor definition, error sources, and the precise mapping from fluctuation operators to the final rate expression. It serves as the single reference for prefactor methodology used by Paper 3.
Igor Grčman (Mon,) studied this question.