No abstract

Limits at 90% c.l. on the square of the mixing strength |U τ 4 | 2 between ν τ and a mostly isosinglet heavy neutrino with mass in the range 10-290 MeV/c 2 are reported. The results were derived using the negative result of a search for neutral particles decaying into two electrons conducted by the CHARM collaboration in a neutrino beam dump experiment. Upper limits ∼ = 10 −4 were obtained for neutrino masses larger than 160 MeV/c 2 .

After completion of the data taking for the v(mu) -> v(tau) oscillation search, the CHORUS lead-scintillator calorimeter was used in the 1998 run as an active target. High-statistics samples of charged-current interactions were collected in the CERN SPS west area neutrino beam. This beam contained predominantly muon (anti-)neutrinos from sign-selected pious and kaons. We measure the flux and energy spectrum of the incident neutrinos and compare them with beam simulations. The neutrino-nucleon and anti-neutrino-nucleon differential cross-sections are measured in the range 0.01 < x < 0.7, 0.05 < y < 0.95, 10 < E-v < 200 GeV. We extract the neutrino-nucleon structure functions F-2(x, Q(2)), xF(3) (x, Q(2)), and R(x, Q2) and compare these with results from other experiments. (c) 2005 Elsevier B.V. All rights reserved