European Organization for Nuclear Research

We present the results of a search for νμ → νe oscillations in the NOMAD experiment at CERN. The experiment looked for the appearance of νe in a predominantly νμ wide-band neutrino beam at the CERN SPS. No evidence for oscillations was found. The 90% confidence limits obtained are ∆m2 < 0.4 eV2 for maximal mixing and sin(2θ) < 1.4 × 10−3 for large ∆m2. This result excludes the LSND allowed region of oscillation parameters with ∆m2 & 10 eV2. Submitted to Physics Letters B We dedicate this paper to the memory of our friend and colleague Gianni Conforto 1) LAPP, Annecy, France 2) Johns Hopkins Univ., Baltimore, MD, USA 3) Harvard Univ., Cambridge, MA, USA 4) Univ. of Calabria and INFN, Cosenza, Italy 5) Dortmund Univ., Dortmund, Germany 6) JINR, Dubna, Russia 7) Univ. of Florence and INFN, Florence, Italy 8) CERN, Geneva, Switzerland 9) University of Lausanne, Lausanne, Switzerland 10) UCLA, Los Angeles, CA, USA 11) University of Melbourne, Melbourne, Australia 12) Inst. for Nuclear Research, INR Moscow, Russia 13) Univ. of Padova and INFN, Padova, Italy 14) LPNHE, Univ. of Paris VI and VII, Paris, France 15) Univ. of Pavia and INFN, Pavia, Italy 16) Univ. of Pisa and INFN, Pisa, Italy 17) Roma Tre University and INFN, Rome, Italy 18) DAPNIA, CEA Saclay, France 19) Univ. of South Carolina, Columbia, SC, USA 20) Univ. of Sydney, Sydney, Australia 21) Univ. of Urbino, Urbino, and INFN Florence, Italy 22) IFIC, Valencia, Spain 23) Rudjer Bošković Institute, Zagreb, Croatia 24) ETH Zürich, Zürich, Switzerland ∗) Deceased ∗∗) Now at Univ. of Perugia and INFN, Italy