Daya Bay Reactor Neutrino Experiment
The Daya Bay experiment is a neutrino experiment in the People's Republic of China to measure the last unknown neutrino mixing angle θ13. The experiment is located about 52 km north of Hong Kong and 45 kilometers east of the city center of Shenzhen and is operated by a multinational research group involving scientists from the People's Republic, Taiwan, the United States, Czech Republic and Russia. It is considered as the most important international research project in China and the first major collaboration between China and the United States in basic research.
Describe the three neutrino mixing angle, how often transitions between the different types of neutrinos are expected. Two of these mixing angles are known for some time after the last unknown value θ13 are searched in various experiments around the world. He relates to the conversion of electron neutrinos into other types. The angle is determined indirectly by a deficit of detected antineutrinos is measured, which are produced in the six reactor units of the nearby nuclear power plants Daya Wan and Ling'ao.
These eight neutrino detectors are built, four of which about 400 meters from the reactors, the other four at a distance of approximately 1,700 meters. From the comparison of the measured neutrino rates in the near and far from the reactors remote detectors can be concluded that a deficit which in turn suggests a conversion to non-detectable neutrino. This approach is similar to the Double to the competing experiments Chooz in France and RENO in Korea.
On 8 March 2012, the Daya Bay group published a paper in which with a significance of 5.2 standard deviations was determined by a non-zero mixing angle θ13:
The measurement is consistent with earlier, but not statistically significant results from T2K, MINOS and Double Chooz and is often regarded as the most important result in the history of Chinese Physics. The fact that the mixing angle θ13 is not zero, but also is comparatively large, gives additional impetus for further exploration of CP violations, which can now in principle be measured with neutrino oscillations. CP- injury may explain why the universe is composed almost entirely of matter and not antimatter.