Status of the OPERA experiment

The OPERA experiment in the underground Gran Sasso Laboratory (LNGS) has been designed to perform the first detection of neutrino oscillations in direct appearance mode in the muon to tau neutrino channel. The detector is hybrid, being made of an emulsion/lead target and of electronic detectors. It is placed in the CNGS neutrino beam 733 km away from the neutrino source. Runs with CNGS neutrinos were successfully carried out from 2008 and the following years. The analysis of a sample of events corresponding to 1.89x10(19) p.o.t. in the CERN CNGS nu(mu) beam yielded the observation of a first candidate nu(tau) CC interaction. The topology and kinematics of this candidate event is described in detail. The background sources are explained and the significance of the observation of the first nu(tau) event candidate is assessed.