June 1, 2010
Scientists Make Breakthrough Physics Discovery
On Monday, scientists in Europe said they have solved the case of the missing neutrinos, one of the enduring mysteries in the subatomic universe of particle physics.
The researchers said the findings challenge core precepts of the so-called Standard Model of physics, and could have major implications for our understanding of matter in the universe.
Neutrinos are electrically neutral particles that travel close to the speed of light.
Physicists had observed for years that fewer neutrinos arrived at Earth from the Sun than solar models predict.
That meant either the models were wrong, or something was happening to the neutrinos along the way.
At least one variety called a muon neutrino was actually seen to disappear, lending credence to a Nobel winning 1969 hypothesis that the miniscule particles were shape shifting into a new and unseen form.
For the first time, scientists at Italy's National Institute for Nuclear Physics have observed what neutrinos change into during a process called neutrino oscillation: another type of particle known as tau, according to AFP.
"This will be the long-awaited proof of this process. It was a missing piece of the puzzle," Antonio Ereditato, a researcher at the Institute and spokesman for the OPERA group that carried out the study, told AFP news.
"If true, it means that new physics will be required to explain this fact," he said.
Under the prevailing Standard Model, neutrinos cannot have mass. However, new experiments prove that they do.
One implication is the existence of other, as yet unobserved types of neutrinos that might help bring light on the nature of Dark Matter, which is thought to make up 25 percent of the universe.
"Whatever exists in the infinitely small always has repercussions in the infinitely big," Ereditato told AFP.
"A model which could explain why the neutrino is so small without vanishing will have profound implications for the understanding of our universe -- how it was, how it evolved, and how it will eventually die."
The transformation of the neutrino occurred during a programmed journey from Geneva to the Gran Sasso Laboratory near L'Aquila in central Italy.
The European Organization for Nuclear Research (CERN) furnished a laser-like beam composed of billions upon billions of muon neutrinos that took only 2.4 milliseconds in order to make the 453-mile trip.
The rarity of neutrino oscillation bedeviled the scientists.
Neutrinos are not sensitive to the electromagnetic field normally used by physicists to bend the trajectory of particle beams, unlike charged particles.
Neutrinos can also pass through matter, and thus keep the same direction of motion from the inception.
It took close to four years from the time the beam was switched on to witness the muon-to-tau metamorphosis.
Image Caption: Lateral view of OPERA. Credit: CERN
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