Strange Effects: The Mystifying History of Neutrino Experiments

via Wired: Wired Science by Adam Mann on 3/9/12

<< Previous | Next >>
What is a Neutrino?

  • What is a Neutrino?
  • Beta Decay Puzzle
  • Neutrinos Discovered
  • The Solar Puzzle
  • The Atmospheric Puzzle
  • A New Neutrino?
  • More Strangeness
  • Future Experiments

Late last year, scientists with the OPERA collaboration in Gran Sasso, Italy reported an incredible finding: neutrinos that appeared to be moving faster than the speed of light.
The news spread at a barely slower pace, fascinating the public. One thing everyone knows is that a very famous physicist named Albert Einstein once said that nothing should travel faster than light speed.
In February, the OPERA researchers found a couple small problems with their experimental set-up, calling into question the original faster-than-light neutrino result. The event highlighted the difficulty of science at the edge of the unknown — and neutrinos are especially tricky.
More often than not, neutrino experiments throughout history have turned up perplexing results. While most of these experiments didn’t get the high-profile attention that disputing Einstein provides, they’ve challenged scientists and helped them learn ever more about the natural world.
In this gallery, we take a look at some of the strangest historical neutrino results and the findings that still have scientists scratching their heads.

What Is a Neutrino?

Neutrinos are tiny, elusive and very common. For every proton or electron in the universe there are at least a billion neutrinos.
Researchers need to know how neutrinos work because they’re relevant to many areas of physics. These ubiquitous specks came into existence milliseconds after the Big Bang, and new neutrinos are created during the radioactive decay of elements, nuclear reactions within stars and the explosive collapse of supernovas.
“They’re one of the dominant particles in the universe but we still know very little about them,” said physicist Bill Louis of Los Alamos National Lab, co-spokesperson for the MiniBooNE neutrino experiment.
Neutrinos are so hard to study because they barely interact with other matter. Unlike the more familiar electron, they have no electromagnetic charge. They pass as easily through lead walls as through mist, and are so light that scientists long thought they had no mass at all. Detecting them requires closely watching a large tank of material, such a water, on the off chance that a neutrino will hit another particle and produce an observable change.
Image: Researchers sit in a boat inside the Super-Kamiokande neutrino experiment in Japan. The detector is made from a tank filled with 50,000 tons of water and lined with more than 11,000 photomultiplier tubes. (Kamioka Observatory/ICRR/University of Tokyo)