Results from the NOMAD experiment

The NOMAD experiment has sought νμ ↔ ντ oscillations by looking for the emergence of τ- in events from the CERN SPS neutrino beam. With some improvements in the techniques of analysis in relation to the results published previously and with the inclusion of data from the 1998 run, no evidence for the oscillations has been found, which results in an updated limit on the oscillation probability [P(νμ → ντ) < 0.5 x 10-3 at a 90% C.L.]. The corresponding limit on the oscillation mixing angle is given by sin22θμτ < 1.0 x 10-3 for large Δm2. By using a 1% contamination of νe in the neutrino beam, we can also rule out νe ↔ ντ oscillations and constrain the probability of the relevant transition as P(νe → ντ) < 3 x 10-2 at a 90% C.L. (sin22θeτ < 6 x 10-2 at large Δm2)