0000000000235809
AUTHOR
S. N. Tovey
Search for eV (pseudo)scalar penetrating particles in the SPS neutrino beam
We carried out a model-independent search for light scalar or pseudoscalar particles $a$'s (an example of which is the axion) that couple to two photons by using a photon-regeneration method at high energies allowing a substantial increase in the sensitivity to $eV$ masses.\ The experimental set-up is based on elements of the CERN West Area Neutrino Facility (WANF) beam line and theNOMAD neutrino detector.\ The new particles, if they exist, could be produced through the Primakoff effect in interactions of high energy photons, generated by the 450 $GeV$ protons in the CERN SPS neutrino target, with virtual photons from the WANF horn magnetic field.\ The particles would penetrate the downstre…
Precision measurement of scaled momentum, charge multiplicity, and thrust in νμN and interactions
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Inclusive production of ρ0(770), f0(980) and f2(1270) mesons in νμ charged current interactions
The inclusive production of the meson resonances $\rho^{0}(770)$, $f_0(980)$ and $f_2(1270)$ in neutrino-nucleus charged current interactions has been studied with the NOMAD detector exposed to the wide band neutrino beam generated by 450 GeV protons at the CERN SPS. For the first time the $f_{0}(980)$ meson is observed in neutrino interactions. The statistical significance of its observation is 6 standard deviations. The presence of $f_{2}(1270)$ in neutrino interactions is reliably established. The average multiplicity of these three resonances is measured as a function of several kinematic variables. The experimental results are compared to the multiplicities obtained from a simulation b…
New results on a search for a 33.9 MeV/c2 neutral particle from π+ decay in the NOMAD experiment
We report on a direct search in NOMAD for a new 33.9 MeV/c^2 neutral particle (X) produced in pion decay in flight, pi-->mu_X followed by the decay X -->nu e^+e^-. Both decays are postulated to occur to explain the time anomaly observed by the KARMEN experiment. From the analysis of the data collected during the 1996?1998 runs with 4.1×10^19 protons on target, a single candidate event consistent with background expectations was found. The search is sensitive to a pion branching ratio BR(pi-->muX >3.7×10^-15, significantly smaller than previous experimental limits.
A study of quasi-elastic muon neutrino and antineutrino scattering in the NOMAD experiment
We have studied the muon neutrino and antineutrino quasi-elastic (QEL) scattering reactions ($\nu_\mu n\to \mu^- p$ and $\bar{\nu}_\mu p\to \mu^+ n$) using a set of experimental data collected by the NOMAD collaboration. We have performed measurements of the cross-section of these processes on a nuclear target (mainly Carbon) normalizing it to the total $\nu_\mu$ ($\bar{\nu}_\mu$) charged current cross-section. The results for the flux averaged QEL cross-sections in the (anti)neutrino energy interval 3-100 GeV are $\sigma^{qel}_{\nu_\mu} = (0.92 \pm 0.02 (stat) \pm 0.06 (syst))\times 10^{-38} \cm^2$ and $\sigma{qel}_{\bar{\nu}_\mu} = (0.81 \pm 0.05 (stat) \pm 0.08 (syst))\times 10^{-38} \cm…