OPERA: A first tau-neutrino appearance candidate

OPERA is a long-baseline neutrino experiment dedicated to the study of muon-neutrino to tau-neutrino oscillation. Using the high-energy CERN neutrinos to Gran Sasso beam (CNGS), it is the first experiment directly searching for tau-neutrino appearance from oscillation of muon-neutrinos. Since 2008 runs with CNGS neutrinos have been successfully accomplished. After a brief introduction on the OPERA hybrid detector and the main parameters of the experiment, recent results are presented. A first candidate for a tau-neutrino charged-current event is described in detail. The background and the corresponding significance of the event is evaluated.