First results from Double Chooz

25 January 2012

Physicists at the Double Chooz experiment have found an indication of a disappearance of electron-antineutrinos that is consistent with neutrino oscillations.

The Double Chooz experiment, which detects antineutrinos produced in the nearby nuclear reactor at Chooz in the French Ardennes, started data-taking in April 2011. The collaboration announced its first results seven months later at the 2011 LowNu conference held in Seoul, reporting new data consistent with short-range oscillations.

The result, on the disappearance of antineutrinos compared with the expected flux from the reactor, helps to determine the so-far unknown third neutrino-mixing angle, θ13. The observed deficit indicates oscillation with the following value: sin213 = 0.086 ± 0.041 (stat.) ± 0.030 (syst.) or, at 90% CL, 0.015 < sin213 < 0.16.

The measurement of this last mixing angle is important for future experiments aimed at measuring leptonic CP violation and relates indirectly to the matter–antimatter asymmetry in the universe.

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