The electron neutrino is recognized as the particle with the smallest non-zero mass among known particles, although its mass is not well-defined due to its superposition of three neutrino mass eigenstates. The discussion highlights that if the lightest neutrino were to have zero mass, it would lead to a determinant of the mass matrix being zero, which does not necessarily eliminate neutrino oscillations. Instead, oscillations can only be prevented by setting mixing angles to zero or making neutrino mass states degenerate. The conversation emphasizes the complexity of neutrino mixing and the importance of proper training to understand these concepts.
PREREQUISITESPhysicists, students of particle physics, and researchers interested in the fundamental properties of neutrinos and their role in the universe.
mathman said:The electron neutrino has the smallest non-zero mass of all known particles.
Parlyne said:The electron neutrino doesn't have a well-defined mass. It's a superposition of the three neutrino mass eigenstates, the lightest of which is the lightest know fermion. However, it is not know whether the lightest neutrino has a non-zero mass.
chrispb said:If the lightest neutrino had zero mass, then the determinant of the mass matrix would be 0 and neutrino oscillations would not occur.
Parlyne said:You are correct that the determinant would be 0; however, I believe that you are incorrect that that would eliminate oscillations. As far as I know, the only ways to prevent oscillations are to set mixing angles to 0 or to make neutrino mass states degenerate. Neither of these possibilities are guaranteed by a 0 determinant.