Monday, June 28, 2010

Small things can make all the difference

Neutral, immeasurably small and more common than Ray Bans on hipsters; and yet despite their abundance, neutrinos have proven frustratingly hard to nail down. In part, because they rarely interact with other matter and pass freely through everything around us.

A group of physicists at Fermilab might have just made major strides in our understanding of neutrinos though.

We've known for some time that neutrinos come in three varieties: electrons, muons and taus. However, in the '90s an experiment at Los Alamos suggested there could be another - the "sterile" neutrino, so named because it's even more reluctant to interact with matter.

The idea is very appealing because it could answer the dark matter question and it's thought you would need to use gravity waves to detect them. But in 2007 a Fermilab experiment, named MiniBooNE, seemingly disproved the idea by failing to find them.

But MiniBooNE brought the issue back to the surface earlier this month when it announced at a conference in Greece that it may have given up too soon on sterile neutrinos.

While the Los Alamos group had used antineutrinos in their experiment, MiniBooNE had made use of neutrinos under the premise that the two should behave the same. Recently, the group decided to take a second look using the same method Los Alamos had and to their great delight, they found the same thing.

A Fermilab physicist, Dan Hooper, suggested in a New Scientist article that the odd behavior might be a result of antineutrinos being able to change into sterile neutrinos, but neutrinos cannot.

The same article also suggests that an apparent flaw in matter-antimatter symmetry like this could explain why there is more matter than antimatter in the universe.

Check out the New Scientist article popping up all over

http://www.newscientist.com/article/dn19072-sterile-neutrino-back-from-the-dead.html

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