http://www.upi.com/Science_News/201...ment-sees-neutrino-oscillation/8261439039952/ The NOvA experiment at Fermilab is already proving a success. Scientists at the U.S. Department of Energy's Fermi National Accelerator Laboratory have reported observing neutrino oscillation. Neutrinos are neutral subatomic particles unaffected by most atomic forces and with only a smidgen of mass. They're produced by a variety of high-energy reactions, including the Big Bang, solar fusion, supernovas and nuclear reactions. What makes them so fascinating is that they can travel directly through matter as if it wasn't there. They also oscillate, changing from one type to another -- from muon neutrinos to electron neutrinos. The NOvA experiment was designed to produce and study neutrinos' unique behavior. So far, so good. Researchers announced their early successes at the American Physical Society's Division of Particles and Fields conference in Ann Arbor, Mich., this week. The ability to oscillate establishes the existence of mass, which had been questioned until earlier research showed oscillation from solar neutrinos. This experiment clinches it.
As they are so penetrating they are hard to detect. Bethe's detailed model of solar fusion, was well confirmed except it predicted several times more neutrinos than were measured (deep inside the earth in old mines)*. Eventually, it was postulated that the "absent neutrinos" had switched to the other form, which is even harder to detect, during their ~ 8 minute transit from the sun. - Quite an outlandish suggestion at the time, until first confirmed. * There is a funny and I think true story related to the detector, which had a huge volume of carbon tetra chloride. (rail road tanks cars of it.) A sales man of coat hangers learned of this large shipment of CCl4 to small town in US upper mid west and as the only volume use of CCl4 was for dry cleaning, appear at the research top side office, hoping for large sale of his coat hangers. Moral: Sometimes the invisible hand of Adam Smith, that normally makes "free-enterprise" much more efficient and better at meeting public needs, than "centrally planned economies" does give a "bum steer."
The first four paragraphs were taken verbatim from the article. Only the last is original to Walter Wagner which explains the awkward phrasing. If the existence of neutrino mass was only questioned up until the research with solar neutrinos, then what possible purpose would this research with laboratory-generated neutrinos serve? What is the thing being clinched? The purpose of current research is to improve knowledge of model parameters and to rule out the possibility of other models. NOvA is hoping to find very subtle signals, so lots of data from lots of different events will be needed. Original NOvA Press Release Fermilab is set up outside Batavia, Illinois where it fires a proton beam slightly downward into NuMI targets generating neutrino beams that traverse the Earth to the detector, up to six miles underground at the midpoint. Ash River, Minnesota is where the NOvA detector is scheduled to be fully operational in November. It's been in partial operation since February. Some other accelerator beam neutrino oscillation results: K2K: http://arxiv.org/abs/hep-ex/0212007 MINOS: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.101.131802 OPERA: http://iopscience.iop.org/1742-6596/631/1/012056 Other evidence came from solar and reactor neutrinos. The 2002 Physics Nobel prize was awarded in part for creation of the field of neutrino astronomy. Neutrino oscillations went from theoretical possibility to clearly evidenced phenomena during the period 1998-2002 as evidence rapidly piled up. http://www.nobelprize.org/nobel_prizes/physics/laureates/2002/advanced-physicsprize2002.pdf
The existence of oscillation is what's being "clinched". This is just one more piece of confirming evidence. Sorry for the akward terminology, but most readers I believe understood the message. Thanks for the links. Since most physics texts until the 21st century referred to neutrinos as 'massless, or possibly a very very small mass', it is refreshing to have ample evidence of their oscillation to establish they are not massless particles, and travel quite fast, but less than c.
This is greater news than would be suggested by the article for the following reason. The original neutrino detector of Ray Davis, operated by an associate of mine who is a physics professor at CUNY, consisted of an underground tank of perchloroethane. Whenever one of the outer chlorine atoms of a perchlorethane molecule in the tank was struck by a solar neutrino (not known then to oscillate), it sometimes changed the chlorine atom into an atom of Argon, an inert gas which remained in the tank. Once every week or so, the tanks were processed to count the number of Argon atoms that had transmuted by the solar neutrino flux. This primitive neutrino detector only detected about 1/3 of the solar neutrino flux because only one of the three oscillation modes interacted with the perchloroethane. The mystery of the missing solar neutrinos was solved over 30 years later by the photomultiplier detectors in the heavy water facility at Sudbury, Ontario. They were able to detect the rest of the solar neutrino flux, which exactly matched the flux predicted by computer models of the inner workings of the Sun, and nailed the exact age of our Sun to a very high degree of accuracy. It was suspected (but not previously confirmed until the FermiLab experiment in the article) that a neutrino burrowing through the Earth would interact with the ELECTROWEAK part of atomic structure, and thereby change mode of oscillation to one of the three possible states. So how might such information be useful? For one thing, you might be able to use the Earth itself as a neutrino modulator. If you knew how much Earth a stream of neutrinos needed to pass through in order for a certain percentage of them to change state, and with a sufficient knowledge of the substrata of the Earth (probed at various points with the neutrinos in order to establish a baseline), then it should be possible to modulate a stream of neutrinos simply by directing two streams of neutrinos through different density geological strata to a distant detector on the surface of the Earth. Handy for predicting Earthquakes, perhaps, but also for public key encryption of sensitive communications that might otherwise be compromised by uplinking it through a satellite transponder. Such communications may be at low data rates to begin with, but it's definitely a start to a new paradigm of terrestrial telecommunications.
