Friday, December 09, 2011

Another Ghost Particle?

Neutrinos, though ghostly and very difficult to detect, have been solving physics mysteries since 1930. Now an even more ghostly fourth neutrino may solve discrepancies involving the three known varieties.



Physicist Wolfgang Pauli first proposed the existence of the neutrino to account for mysteriously missing energy, momentum and spin in radioactivity measurements. Although a neutrino would conveniently solve the experimental problems, the properties of the particle led Pauli himself to bet a case of champagne that it would never be detected. At the time, many physicists suspected that the ghostly neutrino was little more than a mathematical trick - essentially an accounting sleight-of-hand - to mask our ignorance of physics at the nuclear level. Indeed, fifteen years passed before anyone found a way to directly detect neutrinos that exactly matched Pauli's prediction.

It looks like the same drama may play out again. The three varieties of neutrinos (electron neutrinos, muon neutrinos, and tau neutrinos) can spontaneously transform from one to the other through so-called neutrino oscillations that are predicted by modern physics theory. The problem is they seem convert to electron neutrinos 3% more often than they should.

It could be that the apparent overabundance of electron neutrinos is simply the experimental error that comes with trying to count nearly undetectable particles. Or, as some physicists propose, there may be yet another variety of neutrino contributing to the oscillations. If it exists, the new neutrino will be even harder to find that the other three because it has almost no interaction with any other types of matter. It will also throw a wrench into some otherwise pretty solid theoretical models.

The chances are, there is no fourth neutrino. But I'm not betting any champagne on it.

1 comment:

  1. Hey

    Looks to me very simple Quantum Mechanics...The more you try to focus accurately there would be always an displacement which would be an extra nuetrino oscillating...though at a very small percentage...
    3% extra...
    then 0.5% extra...
    then 0.0007 extra of the original 100% ...

    However the smaller the percentage, would not necessarly mean the effect is also small, it might be quite reverse...like the smallest particle might totally reverse the results of all the other neutrinos...

    Deepak

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