Physicists Shoot Neutrinos Across Japan to an Experiment in an Abandoned Mine

By Andrew Moseman | March 1, 2010 5:26 pm

super_kamiokandeWhile the oft-troubled Large Hadron Collider is starting back up today after a weekend glitch, another big physics project is under way halfway around the world. The British and Japanese researchers behind the project called T2K (Tokai-to-Kamioka) announced their first neutrino detection, the initial step in an experiment to understand these mysterious subatomic particles.

Neutrinos are tiny particles that rarely interact with matter, making them incredibly difficult to study. But physicists have done it by looking for the signature left behind when one of the torrent of neutrinos flying through the Earth at any given time happens to crash into the nucleus of an atom within view of a neutrino detector. Japan’s Super Kamiokande is one of the largest neutrino detectors, and now it has a new mission under the T2K project. The goal is to understand a strange kind of subatomic metamorphosis. These particles come in three types or flavours: electron, muon and tau neutrinos. From earlier experiments, physicists know that neutrinos spontaneously change their flavour, oscillating back and forth from one kind to another. But the details are still hazy [New Scientist].

To study this, the scientists are creating their own stream of neutrinos at a facility near the town of Tokai north of Tokyo. That beam is aimed at the Super Kamiokande in Kamioka (thus the name Tokai-to-Kamioka), and travels about 185  miles to get there. The Super-Kamiokande detector is buried in an old zinc mine 3,250 feet under Mt. Ikena near Kamioka in the Japanese Alps. The massive cylindrical detector contains 12.5 million gallons of ultra-pure water and is lined with an acre of photomultiplier tubes, which detect light from neutrino collisions and convert it into an electrical signal [Los Angeles Times].

And beyond the fact that chasing ghost particles with water tanks built in an abandoned mine is just plain cool, team member David Wark says his grander hope is that the study has something to say about the antimatter-matter question. That is, why do we live in a universe dominated by matter, instead of one where antimatter and matter annihilated each other after the Big Bang? “That tells us there must be a law of physics that is different for matter and antimatter. We don’t know what it is, but neutrino oscillations are someplace where it might show up” [New Scientist], he says.

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Image: Super Kamiokande

CATEGORIZED UNDER: Physics & Math
  • NewEnglandBob

    “That tells us there must be a law of physics that is different for matter and antimatter. We don’t know what it is, but neutrino oscillations are someplace where it might show up”

    Ethan Seigal has something to say on this:
    http://scienceblogs.com/startswithabang/2010/03/the_greatest_story_ever_told_-_4.php

  • Georg

    “that neutrinos spontaneously change their flavour, oscillating back and forth from one kind to another. ”

    Utterly wrong, shame on you.
    Neutrino oscillation is from particle to the correspondimg
    antiparticle.

  • Joe

    ““that neutrinos spontaneously change their flavour, oscillating back and forth from one kind to another. ”

    Utterly wrong, shame on you.
    Neutrino oscillation is from particle to the correspondimg
    antiparticle.”

    Not true, it is the change from electron neutrinos – muon neutrinos – tauon neutrinos, changing flavour, for example the electron-neutrinos measured from the sun are 1/3 that of expected, because they oscillate between the flavours… not lepton number (ie particle to anti-particle)

  • http://myhoustonlocksmith.com Jimmy Lee

    Wow! What a cool experiment!
    I am really looking forward to reading what they discover about neutrinos!

    I would like to know this too:

    “That is, why do we live in a universe dominated by matter, instead of one where antimatter and matter annihilated each other after the Big Bang?”

  • http://www.houstonsafeandlock.net locksmith houston

    Hey, I’ve been studying neutrinos at school so I’m glad I found this post! Did you know that neutrinos were first brought to the world in 1930 by Wolfgang Pauli? What I want to know is what is an anti-neutrino? Aha, I may have found the answer. I s this correct:

    The differences consist of lepton number and helicity — both of which may not be good quantum numbers for the neutrino. So they might be identical, but we are not yet sure.

  • http://www.greensurfshop.com/brands/HippyTree.html HippyTree

    This has to be one of the COOLEST experiments that I have ever read about! How fun would that be to say that your job is blast neutrinos!? Must be pretty complicated stuff though.

  • http://www.lightmandalas.co.uk/glasstiles.html Glass Tiles

    This sort of thing makes my mind spin, but it is certainly fascinating!

  • http://www.rephandbags.com Coach Dog Collar

    Truly amazing. I saw a documentary recently on the Science channel regarding neutrinos and it’s crazy how difficult they are to detect. I know you wrote this post a few months ago. Is their any update with regard this study? Is it still going on?

  • http://www.flooringandcarpetskent.co.uk flooring kent

    It’s hard to imagine just how much work has gone into this project and the size of the brains of the people behind it. Makes me feel kind of dumb.

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