Results from the NOMAD experiment on νμ ⇆ ντ oscillations

The NOMAD experiment has been searching for nu(mu) <-> nu(tau) oscillations by looking for the appearance of tau(-) in events from the CERN-SPS neutrino beam. With a significant improvement in the analysis techniques with respect to the previous published results and including data from 1995 to 1997, no evidence for oscillations is found, resulting in an updated limit in the oscillation probability of P(nu(mu) <-> nu(tau)) < 0.6 x 10(-3) at 90% C.L. This corresponds to a limit on the oscillation mixing angle of sin(2) 2 theta(mu tau) < 1.2 x 10(-3) for large Delta m(2). By using the 1% contamination of nu(e) in the neutrino beam we can also exclude nu(e) <-> nu(tau) oscillations with a probability of P(nu(e) <-> nu(tau)) < 4 x 10(-2) at 90% C.L. (sin(2) 2 theta(e tau) < 8 x 10(-2) at large Delta m(2)).