The amazing disappearing antineutrino

A revised calculation suggests that around 3% of particles of nuclear reactor have disappeared experiments.Measurements of the Sudbury Neutrino Observatory in Canada were the secrets of the neutrinos probably - settled have new calculations have raised new questions.Roy Kaltschmidt / Lawrence Berkeley NAT ' L lab

Neutrinos have long with physicist with their uncanny ability to detect, more than two-thirds of the ghostly particles apparently go missing way from the Sun to the Earth to escape at a loss. Now a refined version of an old calculation caused a stir caused by suggesting that the researchers have also systematically the number of particles underestimated antimatter partner - antineutrinos - produced by nuclear reactor experiments.

The deficit could be determined not directly by turning in so-called 'sterile anti neutrino', and that would be clear evidence for effects beyond the standard model of elementary particle physics of antineutrinos caused.

Found in the 1960s, the physicist Ray Davis, deep underground in the Homestake gold mine in South Dakota, working the luminous flux of solar neutrinos, the hitting Earth a theorist John Bahcall predicted one-third, of calculations of nuclear reactions in the Sun. Davis later received a Nobel Prize for his contributions to the neutrino Astrophysics. This puzzle was in 2001, when the Sudbury the missing two thirds through an alternative means to detect found resolved Neutrino Observatory (SNO) in Canada. The SNO results were evidence that neutrinos have a mass that allows them to between three varieties oscillation: Electron, muon, and Tau. Davis had recognized only the electron neutrinos.

Results consistent with this theory so far about achieved experiments which the rate of antineutrino production from the decay of uranium and plutonium isotope masses. But the revised calculation1 accepted the conclusion this week of physical review D, that it not the whole story. While waiting for the double Chooz experiment in France to fully functional, neutrino Thierry Lasserre and his colleagues at the French Atomenergie-commission(CEA) in Saclay, set out to predictions about the rate of antineutrino production from nuclear reactors check. A calculation first done repeatedly in the 1980s by Klaus Schreckenbach at the Technical University of Munich, with more modern techniques, which allowed them to be much more accurate.

Their new estimate of the production rate is about 3% more than previously expected. This means that several generations of Neutrino and antineutrino have unknowingly missed a fraction of the particles experiments. "It was quite surprising for us," said Lasserre.

Double Chooz consists of two detectors measure the luminous flux which produced antineutrinos the Chooz nuclear power station in the French Ardennes, a detector, 400 m from the hotel and the other 1 km away. The far detector has been this year.

Stefan Sch?nert, a neutrino physicist to which technical University Munich, says the calculation is solid and has been validated with Schreckenbach. "they can reproduce the results." There is no way to this result. "It is very solid."

Art McDonald of Queen's University in Kingston, Canada and SNO says that people have carefully look at the calculation, which even a systematic error can have. But, he adds, "There is no doubt that it would have significance as a physics result, if it can be shown with more accuracy."

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The result can one so "sterile" version, which interact with ordinary matter, not says that Carlo Giunti, a physicist at the University of Turin will show in Italy on the detection of neutrinos and antineutrinos, oscillating in a fourth type of neutrino or antineutrino. Other experiments have evidence for sterile particles, including the liquid scintillator neutrino detector at the Los Alamos National Laboratory in New Mexico and the mini booster neutrino experiment or MiniBooNE, at Fermilab in Batavia, Illinois, seen and the search to confirm their existence is a hot area of physics.

Giunti says that the extent of the anomaly by Lasserre clearly were not statistically significant on its own, but that you promising cooperation, pointing in the same direction as a further anomaly by the sages Neutrino Observatory in the Caucasus 20052 studied the neutrinos from radioactive sources on the Baksan found. "Before there was a contradiction earlier experiments between [reactor and radioactive source], but now they agree", Giunti says.

Sch?nert says, that one important experiment is a measurement each shows that the rate of disappearance of antineutrinos from a source with the distance increases. "This would be the smoking gun," he says.

Mention, G. et al. http://arxiv.org/abs/1101.2755Abdurashitov, j. N. et al. find something offensive or inappropriate http://arxiv.org/abs/nucl-ex/0512041If or which otherwise complies with our terms or Community guidelines, select the link "report this comment".Comments on this thread are marked according to the time of booking.

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