Assumptions
At a lecture for the general public by one involved in this experiment the discovery of Neutrinos having mass is based on assumptions. They "proved" the Sun produces two maybe three thypes of Neutrinos. They assume it produces one type but the other two types are the result of the first type being changed during the journey , If the Sun directly produces the two or three types of neutrinos, the evidence for Neutrinos having mass fails. If change can occur without mass, again the evidence fails.
The Star of Bethlehem: Science, History, and Meaning
But now, thanks in part to the neutrino detection facility in an abandoned mine in Sudbury Ontario, researchers have discovered that neutrinos do have a mass, although an extremely small mass. Neutrinos carry off the bulk of the energy of a supernova explosion