A non zero, surprisingly large value of the third mixing angle $theta_{13}$ has been measured in reactor neutrino experiments. Currently the most precise measurement of $sin^2 2theta_{13}$ has been performed by the Daya Bay experiment $sin^22theta_{13}=0.089pm 0.010({rm stat.})pm0.005({rm syst.})$ (7.7 $sigma$ significance of $sin^22theta_{13} > 0$),the RENO experiment has measured the value $sin^2 2theta_{13} = 0.113 pm 0.013(rm stat.) pm 0.019(rm syst.)$ (4.9 $sigma$ significance) and the Double Chooz experiment $sin^2 2theta_{13} = 0.109 pm 0.030(rm stat.) pm 0.025(rm syst.)$ (2.9 $sigma$ significance). These results are extremely important for future searches of violation of combined CP parity in lepton sector of the Standard model.
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