The OPERA experiment status (16th YKIS Conference, Progress in Particle Physics 2008)
The OPERA experiment is aimed at observing ν_μ to ν_τ oscillation by detecting appearance of ν_τ interactions. OPERA detector is located in Gran Sasso Laboratory (LNGS) underground experimental hall. Muon neutrinos fly from CERN to LNGS (CNGS) about 730km, are expected to be oscillating to tau neutrino about 2% in fraction at the ΔM^2_<23> of 2.4×10^<-3>eV^2. The signal of neutrino oscillation by appearance of tau neutrino charge current interactions will be detected by Emulsion Cloud Chamber (here after ECC). An ECC is composed of 56 lead plate and 57 nuclear emulsion film in sandwich structure and its size is 12.5×10×8 in cm and weight 8.3kg. The neutrino exposure of year 2008 was that of the first year with full target (150,000 ECCs〜1300 ton) installation, collecting about 1700 neutrino interactions in ECC targets and its analysis is going on. The status of OPERA experiment is described here.
素粒子論研究 117(3), C42-44, 2009-08