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trinitree88
2010-Jan-20, 07:36 PM
There is much work done on neutrino oscillations switching flavors while traveling through experiments. However according to the authors, the experiments do not give unequivocal rest masses. SEE:http://arxiv.org/PS_cache/arxiv/pdf/1001/1001.2799v1.pdf

peteshimmon
2010-Jan-20, 09:16 PM
Why are we not surprised I wonder:)

antoniseb
2010-Jan-21, 12:46 AM
If we could find one that is at rest, I wonder how you could go about weighing it... Do you have a little crucible that could hold it?

lpetrich
2010-Jan-22, 12:25 PM
The reason for this under-determination is the nature of neutrino oscillations.

For mass state k, the phase a(k) changes with energy E, rest mass m(k), and distance traveled x as

da(k)/dx = m(k)^2/(2E)

I'm leaving aside interactions with outside matter here, like stellar interiors.

However, we don't observe the effects of phases a(k) directly. We only observe the effects of differences between the mass states' phases: a(k2) - a(k1):

d(a(k2) - a(k1))/dx = (m(k2)^2 - m(k1)^2)/(2E)

Thus, one can find m(2)^2 - m(1)^2 and m(3)^2 - m(1)^2 from neutrino-oscillation data, but not m(1) or m(2) or m(3) individually.