Present status of the opera experiment for the direct observation of neutrino oscillations in the ν_μ → ν_τ channel

The OPERA experiment (Oscillation Project with an Emulsion-Tracking Apparatus) for the direct observation of neutrino oscillations in the νμ → ν τ channel has been underway at the underground laboratory in Gran Sasso since 2007. In the course of data collection, more than 3000 νμ interactions have been registered in emulsion detectors. Twenty charmed neutrino interaction candidates have been found. Multidimensional criteria have been developed in order to select ν τ interactions against νμ interactions accompanied by charmed hadron production. The first results from automated PAVIKOM emulsion scanning have been obtained. We discuss the measurements of the muon charge ratio of μ+ to μ−.