...No wonder the journal Science described the experiment in the field of neutrino oscillations one of the ten scientific achievements of the year.

Antineutrino detector collaborations Daya Bay (photo Heeger Group.)

What is so important did the us-China-Russia-Czech group, known as the collaboration Daya Bay? She just has announced the immediate results of the study of neutrino oscillations, conversion electron, muon, or tonnage the neutrino neutrinos of another variety (generation) or antineutrino.

The experiment is conducted in Daya Bay that in fifty kilometers to the North of Hong Kong (China). The installation consists of a three-neutrino detectors, the source of antineutrino are six nuclear reactors, located half a kilometer from the detectors. The project involves scientists from the Institute of high energy physics, China Academy of Sciences, National laboratory Lawrence Berkeley and Brookhaven national laboratory (both - USA), as well as specialists of the Russian joint Institute for nuclear research.

So, according to research group, sin2 (2?13) = 0,092 ± 0,017 where ?13 corresponds to one of the elements of the matrix Pontecorvo - Maki - Nakagawa - Sakata describing mixing neutrinos and their transition into neutrinos another variety and antineutrino, in other words, themselves neutrino oscillations. In the top line of this matrix are the so-called mixing angles theta 12, theta-23 and theta 13. And if the first two angle is known, the clarification of the exact values of the third, the lowest so far not been carried out.

It ?13, reflecting the mixing angle, which characterizes the possibility neutrino stillyoung, was measured by a scientific team with hitherto unprecedented accuracy.

The most unexpected was the disappearance of about six percent of the electron antineutrino generated by reactors, but never registered detectors. Of course, they would not disappear, but moved to a different state, becoming the muon or toonami (actually oscillation). The theory of this phenomenon, developed Bruno Maximovich Pontecorvo, argues that the probability of finding a particle of a given sort, depending on elapsed since the establishment of a particle of his time will be changed periodically. It is assumed that such transformations are caused by the presence of the neutrino mass. Such oscillations is commonly attributed the lack of electron neutrinos in the neutrino flux from the Sun.

Although the finding of non-zero values of the mixing angle" and was, in fact, the purpose of the experiment, few expected that this angle would be so great.

In addition, as noted physics, repertorium operators, drawn from the fields of the Standard model at a certain hierarchy between them, can explain neutrino oscillations and baryon asymmetry of the Universe, that is, the dominance of matter over antimatter in the present Universe. The fact of this dominance, on the one hand, it seems obvious (if antimatter and matter was originally equally, they annihilated would, eliminating the formation of stars and other), and with another - is not explained in the framework of the Standard model. That makes the experiment in Daya Bay so important.

Great angle theta 13 says, in particular, that there is a significant asymmetry between neutrinos and antineutrinos (CP-violation), and it explains why antimatter in the Universe now is not observed, and matter, in contrast, seems to dominate.

Based on the materials Phys.Org.