SCIENCE> THE NOBEL PHYSICS PRIZE WAS FOR TWO RESEARCH Neutrinos
A Canadian and a Japanese scientist received the prize for discovering that neutrinos have mass and thereby revolutionize physics subatomic particles. Their discovery changed what was known about the most intimate behavior of matter.
Can something through the human body without the person realize? It can even be crossed billions and billions of times, at all times and at all times? The answer is yes and physics: neutrinos, these particles smaller than the atom, which permanently raining down on Earth and transcend everything that crosses them. Not only people, but also everything around them, until the planet itself. They are the most mysterious particles in the universe, because after all leave no traces through it. And it’s so light and fast they always believed they had no mass. Error. Two scientists showed that do have and it changed the way we understand and explain the subatomic world. These two researchers, one Japanese and one Canadian, yesterday won the Nobel Prize in Physics.
Takaaki Kajita, Japanese, and Arthur B. McDonald, Canadian, actually discovered that neutrinos have oscillations demonstrating that these elementary particles of matter have mass, contrary to what was assumed for decades.
The Royal Swedish Academy of Sciences said in introducing his ruling that such studies “changed our understanding of the behavior more intimate matter and may be crucial to understanding the universe. ” The Nobel honored both for his “contributions to key experiments showed that neutrinos change their identity”, which requires that these particles have mass.
First things first. Where do neutrinos? One of them is formed in the atmosphere by cosmic radiation. Another is produced in nuclear reactions within the sun precisely, the Japanese team set out to capture neutrinos created in reactions between cosmic rays and the atmosphere of the Earth.; the other, trapping from the sun.
The existence of neutrinos, the largest particles in the universe, was suggested by the Austrian Wolfgang Pauli in 1930, although it was the Italian Enrico Fermi who eight years later He developed a theory and baptized the new term. But they were not discovered until a quarter century after two American physicists, Frederick Reines and Clyde Cowan. Since the 1960s science had theoretically calculated the number of neutrinos, but when measuring on Earth found that two-thirds were gone.
Earth reach 60,000 billion neutrinos per square centimeter every second. For decades, the “standard model” of particle physics understood that to reach Earth neutrinos may disappear without explanation. That’s because they could not be detected.
What Kajita and McDonald discovered is that they do not disappear, but change, undergo a metamorphosis. And the fact that they have this mutation means they have mass.
Kajita discovered that neutrinos from the atmosphere passed from one identity to another on his way to the Super-Kamiokande detector, a stunning Japanese neutrino observatory . At the same time, a group of Canadian researchers led by McDonald showed that neutrinos the Sun did not disappear on its way to Earth and could be captured with a different identity upon arrival at the Sudbury Neutrino Observatory, located in Ontario.
Located in a zinc mine 250 kilometers from Tokyo, the gigantic Super-Kamiokande detector began operating in 1996, and three years later did the Sudbury Neutrino Observatory (SNO) in Ontario (Canada) in the within a nickel deposit.
In the Super-Kamiokande, built a thousand meters deep and consists of a tank with 50,000 tons of water, equipment Kajita noted that although most of the neutrinos crossed tank, some colliding with an atomic nucleus or an electron. In such collisions charged particles were created and, around them, faint flashes of blue light, called Cherenkov radiation, which occurs when a particle is generated travels faster than the speed of light and the shape and intensity reveals origin and type of neutrino to the cause.
The Japanese muon neutrino detector caught the atmosphere and beat him down after crossing the globe, and because the Earth does not pose a significant obstacle to they should have equal number of neutrinos in both directions.
The observations revealed, however, that the former were more numerous, which pointed to the others should undergo a change of identity to become neutrinos tau, although its pace could not be registered by the detector.
The crucial piece of the puzzle came from SNO, in a tank with tons of heavy water performed measurements of neutrinos from the sun, where the processes Nuclear lead only to the third type of these particles, electron neutrinos.
Of those 60,000 billion neutrinos per square centimeter every second bombard the Earth, the SNO captured three million per day in its first two years operational, a third of the expected number: the other two were due to change of identity along the way. These oscillations are proving that neutrinos have mass, although it is not known what it is.
What changes that neutrinos have mass? Probably the reader, nothing. For scientists devoted to the subject, everything. The standard model so far described the perfeccción the subatomic world of particle physics ceased to explain everything.
But before we can fully develop theories that exceed this model will need to find out more about the nature of neutrinos, and what their mass or why they are so different from other elementary particles.
The only certainty for now are signs that there is a new physics to the universe that has yet to be discovered . Behold how fascinating for researchers. So fascinating that won the Nobel Prize.
No comments:
Post a Comment