If the presence of a neutrino (or dark mater particle) is required for fission to occur, would this really be testable currently? Maybe there are other effects

If the presence of a neutrino (or dark mater particle) is required for fission to occur, would this really be testable currently? Maybe there are other effects that influence decay that we haven't fully been able to investigate. I'm just saying that we don't know everything yet, and it may be possible to influence these things in some way in the future.