Daya Bay Reactor Neutrino Experiment

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Coordinates: 22°35′43″N 114°32′35″E / 22.5953°N 114.5431°E / 22.5953; 114.5431 The Daya Bay Reactor Neutrino Experiment is a China-based multinational particle physics project studying neutrinos. The multinational collaboration includes researchers from China, the United States, Taiwan, Russia, and the Czech Republic. The US side of the project is funded by the US Department of Energy's Office of High Energy Physics.

It is situated at Daya Bay, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen. There is an affiliated project in the Aberdeen Tunnel Underground Laboratory in Hong Kong. It measures the neutrons produced by cosmic muons which may affect the Daya Bay Reactor Neutrino Experiment.

Neutrino oscillations[edit]

The experiment studies neutrino oscillations and is designed to measure the mixing angle θ13 using antineutrinos produced by the reactors of the Daya Bay Nuclear Power Plant and the Ling Ao Nuclear Power Plant. Scientists are also interested in whether neutrinos are CP violators.

On 8 March 2012, the Daya Bay collaboration announced[1][2][3] a 5.2σ discovery of θ13 ≠ 0, with

 \sin^2 (2\theta_{13}) = 0.092 \pm 0.016 \, \mathrm{(stat)} \pm 0.005\, \mathrm{(syst)}.

This significant result represents a new type of oscillation and is surprisingly large.[4] It is consistent with earlier, but less significant results by T2K, MINOS and Double Chooz. With θ13 so large, NOνA has about a 50% probability of being sensitive to the neutrino mass hierarchy. Experiments may also be able to probe CP violation among neutrinos.

The collaboration produced an updated analysis of their results,[5] which used the energy spectrum to improve the bounds on the mixing angle:

  \sin^2 (2\theta_{13}) = 0.090 +0.008 -0.009

At the Neutrino2014 conference, they showed a result using 621 days of data:

 \sin^2 (2\theta_{13}) = 0.084 \pm 0.005

Collaborators[edit]

References[edit]

  1. ^ Daya Bay Collaboration (2012). "Observation of electron-antineutrino disappearance at Daya Bay". Physical Review Letters 108 (17): 171803. arXiv:1203.1669. Bibcode:2012PhRvL.108q1803A. doi:10.1103/PhysRevLett.108.171803. 
  2. ^ Adrian Cho (8 March 2012). "Physicists in China Nail a Key Neutrino Measurement". ScienceNow. 
  3. ^ Eugenie Samuel Reich (8 March 2012). Neutrino oscillations measured with record precision. NatureNews. doi:10.1038/nature.2012.10202. 
  4. ^ http://neutrino.physics.berkeley.edu/news/News.html
  5. ^ arXiv:1310.6732v2 [hep-ex]

External links[edit]