Evidence for Neutrino Disappearance

decowski writes "Results from the first six months of experiments at KamLAND, an underground neutrino detector in central Japan, show that anti-neutrinos emanating from nearby nuclear reactors are "disappearing," which indicates they have mass and can oscillate or change from one type to another. As anti-neutrinos are the anti-matter counterpart to neutrinos, these results provide independent confirmation of earlier studies involving solar neutrinos and show that the Standard Model of Particle Physics, which has successfully explained fundamental physics since the 1970's, is in need of updating. The results also point the way to the first direct measurements of the total radioactivity of the earth."

Comments

Answering my own question:

[Futurepower(R)]

Answering my own question:

I sent and email to KamLAND, and this was the answer:

"Not really. I haven't heard of any mine caverns collapsed because of an earthquake in Japan. Much bigger risk is the human-induced quakes because of the blasts and instability due to large caverns in a mine. This of course can happen anywhere. SNO for example saw quite a big quake in the Sudbury nickel mine this way even though it is geologically old and stable."

Hitoshi

Minor quibble, or addendum

[aminorex]

I think it's been suspected since 1995 when the Brookhaven Muon g-2 experiment results began to get published, and very clear since 1998 or so, as they expanded and were corroborated, that there are defects, omissions, from the Standard Model that go beyond the little detail of overlooking gravitation.

Check out this search for more info on the anomalous magnetic moment of the muon.

Re:Minor quibble, or addendum

[yomegaman]

I don't think either the g-2 or the neutrino oscillations really pose much problem to the Standard Model, unfortunately. Nonzero neutrino masses can be easily incorporated into the SM, there's nothing there that requires them to be massless. You just add the mass terms to the Lagrangian and throw in a mixing matrix, sure the masses are arbritrary but they are for all other particles too. I don't quite know what to make of the g-2 measurement. After the first results came out there was so much arguing about the theoretical prediction that it started to look like you could get any answer you wanted. First there was a lot of heat about the hadronic correction term, then the light-by-light scattering part turned out to have the wrong sign, etc. It's not at all obvious to me that there is a really firm SM prediction to compare the experimental results too, it's like the kaon mixing epsilon'/epsilon business all over again. The g-2 people seem to be a bit too eager pushing a "new physics" interpretation for my taste, although I guess it's understandable why they are doing it. The last time I looked the discrepancy was 2.2 sigma, which is certainly not 'very clear' evidence that the SM is wrong.

Re:Minor quibble, or addendum

[hubie]

Years ago I was at a conference where the session was on results from air shower detectors. During one talk this fella was saying that you shouldn't believe anything less than 4 sigma anyway. The next guy to talk presented his 3 sigma results from a different experiment.

Whoops... swap former and latter.

[Peter T Ermit]

Neutrinos require mass assumption; g-2 requires supersymmetry or other extension.

this link works (at the moment)

[tqft]

http://www.lbl.gov/Science-Articles/Archive/NSD-Ka mLAND-Freedman.html