Free nucleons propagating in water are known to produce gamma rays, which
form a background to the searches for diffuse supernova neutrinos and sterile
neutrinos carried out with Cherenkov detectors. As a consequence, the process
of nucleon knockout induced by neutral-current quasielastic interactions of
atmospheric (anti)neutrinos with oxygen needs to be under control at the
quantitative level in the background simulations of the ongoing and future
experiments. In this paper, we provide a quantitative assessment of the
uncertainty associated with the theoretical description of the nuclear cross
sections, estimating it from the discrepancies between the predictions of
different models.Comment: 7 pages, 2 figure