A group of more than 260 scientists has produced one of the most stringent tests to date for the existence of theorized sterile neutrinos, which are theorized particles related to the three known types, or “flavors,” of neutrinos but that are not directly detectable. https://newscenter.lbl.gov/2020/08/10/international-physicists-join-forces-in-hunt-for-sterile-neutrinos/