Search for $\nu_{\mu} \to \nu_{\tau}$ oscillations in appearance mode in the OPERA experiment

The OPERA experiment is aiming at the first direct detection of neutrino oscillations in appearance mode through the study of the {\nu}{\mu} {\tp} {\nu}{\tau} channel. The OPERA detector is placed in the CNGS long baseline {\nu}{\mu} beam 730 km away from the neutrino source. The analysis of a sub-sample of the data taken in the 2008-2009 runs was completed. After a brief description of the beam and the experimental setup, we report on event analysis and on a first candidate event, its background estimation and statistical significance.