Random Thoughts on the Universe

Monday, June 21, 2010

Neutrinos are Weird

Perhaps we already knew that they were weird, but they are getting weirder as more data is published. Several years ago it was discovered that the three types of neutrino can change species. So if you produce an electron-type neutrino, a few km away it becomes a muon-type neutrino, and maybe later changes into a tau-type neutrino. The neutrino is perhaps the only fundamental particle that can do this trick.

Well it got worse this week. The MINOS experiments has been measuring the oscillations of muon neutrinos and anti-muon neutrinos. Theoretically they should give identical results, because every (confirmed) experimental data we have completed in the past shows matter and antimatter behave in the same way. (A few weeks ago Fermilab reported some differences in other reactions, but those seem to have been largely discredited now)
But MINOS has discovered a rather large discrepancy in the muon neutrino and anti-muon neutrino oscillation rates - a difference of about 40%.
The the MiniBOONE experiment, which was measuring the same thing, reported that they are seeing the exact same effect, but with slightly different neutrino reactions.

Obviously more data is going to be needed, but this is an interesting prelinary finding.

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