Can we calculate a lower mass for neutrinos? My argument for a lower mass of $10^{-60}$ plank masses is as follows:
Assume a neutrino has non-zero mass. Then there is a frame of reference where the neutrino is at rest (or has momentum expectation value of zero).
To be detectable within the observable universe it has to have a de-brogile wavelength smaller than the radius of the observable universe (or equivalently frequency less than the age of the universe) which differ at most by a factor of 3. In planck units this is about $10^{-60}$.
Thus assuming you can't go to a frame of reference in which a neutrino suddenly disapears from the universe then it's rest mass must be $>10^{-60}$ planck masses. (This argument doesn't work for massless particles since there is no frame of reference in which they are at rest).
Assuming this is correct is there any way we can push this lower bound upwards? For example, knowing that neutrino oscillations occur within the distance from the Sun to Earth would this put a lower bound on the masses?
(The real masses are probably more closer to $10^{-30}$ Plank masses)
