I am confused about the current physics regarding neutrinos and implications about the conservation laws of mass-energy and linear momentum. I have read the threads listed for similar discussions, including, "How does conservation of energy/mass apply to neutrinos?", and none of them seem to address the issue I am raising here. The following are the "facts" about neutrinos according to current theory as I understand them: Neutrinos have a non-zero rest mass. Neutrinos travel at less than the speed of light. There are three species of neutrinos, each with a rest mass different than the other two. When a neutrino is created it travels at a velocity near the speed of light. That is, it has a relativistic speed. As a neutrino of a given species moves, it randomly changes into another species. When a neutrino interacts, it will become a specific one of the three possible species. The probability that an interacting neutrino becomes any particular species is related to that species rest mass. (What is this relationship?) The following is an interpretation regarding these facts. I am not sure of the status of this interpretation within the physics community. Before a neutrino interacts, it has no individual species. Rather, it is a probabilistic superimposed state of all three species, and it's interaction changes its state into a particular species. If this interpretation is correct, then the neutrino's rest mass and velocity are also not specific until an interaction. However, to satisfy conservation of mass-energy and momentum, these quantities must be the same for all three species. The following are the relativistic equations for these conservation laws. m01, m02, and m03 are the rest masses for the three species, and v1, v2, and v3 are their corresponding linear velocities. It can be shown that if the three rest masses are not all equal, then there are no values for the three velocities that will satisfy these equations. If the masses are equal, then the velocities must also be equal. Does the current theory regarding neutrinos allow violations of the conservation laws? If not, can anyone help me resolve my confusion.