Speaker
Dr
Alain Letourneau
(CEA-Saclay)
Description
The question of the existence of sterile states for neutrinos is addressed since many years. If they exist such states would not be directly detected but could mix with the three ordinary states and would be “seen” as new oscillations in the propagation of the neutrinos. Recently this question arose by the observation of a small deficit of anti-neutrinos with respect to predictions by previous anti-neutrino oscillation experiments at short distance from reactors. If proven, the existence of this particle would be a major discovery, with deep impact in particle physics and cosmology. The goal of the Stereo experiment is to probe the existence of a new oscillation at short distance with a detector located at ten meters from the core of the ILL research reactor. The design of the detector with six independent cells will allow to measure the neutrino energy spectrum as a function of the distance from the core. It follows a running short-range experiment Nucifer where a one–cell detector is placed at 7 m from the core of the Osiris research reactor. Stereo is currently under construction and the data-taking will start at the beginning of 2015.
After a short review of existing experiments searching for a new sterile state, we will describe in detail the Nucifer and Stereo experiments, present the first results from the Nucifer experiment and detail the background problematics and the systematic uncertainty budget. Finally, expected sensitivities on the neutrino parameters, the mixing angle and the squared mass difference, will be presented.
Primary author
Dr
Alain Letourneau
(CEA-Saclay)
