A search for neutrino oscillations via the muonic decay of the $\tau$ lepton at the CERN SPS

The results of a search for the oscillation v u -> v t with the NOMAD experiment at CERN are presented. NOMAD is designed to detect t lepton production events in the SPS wide band v u beam. A 3-ton active target of tracking chambers, a series of TRD modules, a preshower module, and a lead-glass calorimeter are installed in the magnet from the UA1 experiment, approximately 1 km from the v u source. Scintillator calorimeters are installed in the forward and rear magnet elements, and part of the UA1 muon system is placed at the rear of the detector. After a total of approximately 1x10*19 protons on target, no evidence of t production is detected via the decay channel t- -> u - v t v u.