Neutrino oscillation: First results from Double Chooz

Neutrinos have the ability to transform their identity. Thus, an electron-neutrino becomes either a moun- or a tau-neutrino. According to scientists this so called neutrino oscillation depends on three mixing angles. Two angles have been measured before, the property of the third angle, theta13, is still unknown. Only recently, Antonio Palazzo from the Excellence Cluster Universe and his colleagues proved, that a combined analysis of data from sun- and reactor-neutrino experiments indicate that the theta13 parameter is larger than zero. (link to press release). Now the community of neutrino physicists hopes that these indications can be verified experimentally. Just recently, the T2K experiment in Japan brought first results. Only a short time later, the new Double Chooz experiment also delivered an output, which was presented at the LowNu conference in Korea last week.

The Double Chooz experiment was among others initiated by TUM and Cluster scientists. The experiment aims to examine the neutrino oscillation through the observation of antineutrinos. Those antineutrinos are produced in the nearby nuclear power plant at Chooz in the French Ardennes. At the recent LowNU conference the collaboration reported on new data, which are consistent with short-range oscillations. Physicists of the Double Chooz experiment found out that a small amount of electron-antineutrinos disappeared at a distance of about 1000 meters from the reactor to the detector. Therefore, the scientists concluded that the electron antineutrinos adopt a new identity (or “flavor”). For this reason the Double Chooz experiment investigates the mechanism of the neutrino oscillation with the third mixing angle theta13. In combination with the accelerator experiments in Japan and the USA, scientists will in the future also search for indications on leptonic CP violations, in order to unravel the mystery of the asymmetry between matter and antimatter in today’s Universe.