11 research outputs found
Initial Results from the CHOOZ Long Baseline Reactor Neutrino Oscillation Experiment
Initial results are presented from CHOOZ, a long-baseline reactor-neutrino
vacuum-oscillation experiment. Electron antineutrinos were detected by a liquid
scintillation calorimeter located at a distance of about 1 km. The detector was
constructed in a tunnel protected from cosmic rays by a 300 MWE rock
overburden. This massive shielding strongly reduced potentially troublesome
backgrounds due to cosmic-ray muons, leading to a background rate of about one
event per day, more than an order of magnitude smaller than the observed
neutrino signal. From the statistical agreement between detected and expected
neutrino event rates, we find (at 90% confidence level) no evidence for
neutrino oscillations in the electron antineutrino disappearance mode for the
parameter region given approximately by deltam**2 > 0.9 10**(-3) eV**2 for
maximum mixing and (sin(2 theta)**2) > 0.18 for large deltam**2.Comment: 13 pages, Latex, submitted to Physics Letters
Search for neutrino oscillations on a long base-line at the CHOOZ nuclear power station
This final article about the CHOOZ experiment presents a complete description
of the electron antineutrino source and detector, the calibration methods and
stability checks, the event reconstruction procedures and the Monte Carlo
simulation. The data analysis, systematic effects and the methods used to reach
our conclusions are fully discussed. Some new remarks are presented on the
deduction of the confidence limits and on the correct treatment of systematic
errors.Comment: 41 pages, 59 figures, Latex file, accepted for publication by
Eur.Phys.J.
Limits on Neutrino Oscillations from the CHOOZ Experiment
We present new results based on the entire CHOOZ data sample. We find (at 90%
confidence level) no evidence for neutrino oscillations in the anti_nue
disappearance mode, for the parameter region given by approximately Delta m**2
> 7 x 10**-4 eV^2 for maximum mixing, and sin**2(2 theta) = 0.10 for large
Delta m**2. Lower sensitivity results, based only on the comparison of the
positron spectra from the two different-distance nuclear reactors, are also
presented; these are independent of the absolute normalization of the anti_nue
flux, the cross section, the number of target protons and the detector
efficiencies.Comment: 19 pages, 11 figures, Latex fil
Determination of neutrino incoming direction in the CHOOZ experiment and Supernova explosion location by scintillator detectors
The CHOOZ experiment measured the antineutrino flux at a distance of about 1
Km from two nuclear reactors in order to detect possible neutrino oscillations
with squared mass differences as low as 10**-3 eV**2 for full mixing. We show
that the data analysis of the electron antineutrino events, collected by our
liquid scintillation detector, locates the antineutrino source within a cone of
half-aperture of about 18 degrees at the 68% C.L.. We discuss the implications
of this experimental result for tracking down a supernova explosion.Comment: Submitted to Physical Review
Determination of neutrino incoming direction in the CHOOZ experiment and its application to supernova explosion location by scintillator detectors
The CHOOZ experiment has measured the antineutrino flux at about 1 km from two nuclear reactors to search for possible (e)-->(x) oscillations with mass-squared differences as low as 10(-3) eV(2) for full mixing. We show that the analysis of the similar to 2700 (e) events, collected by our liquid scintillation detector, locates the antineutrino source within a cone of half-aperture approximate to 18 degrees at the 68% C.L. We discuss the implications of this result for locating a supernova explosion
Determination of neutrino incoming direction in the CHOOZ experiment and its application to Supernova explosion location by scintillator detectors
The CHOOZ experiment 1 has measured the antineutrino flux at about 1 Km from two nuclear reactors to search for possible e ! x oscillations with mass-squared differences as low as 10 \Gamma3 eV 2 for full mixing. We show that the analysis of the ¸ 2700 e --events, collected by our liquid scintillation detector, locates the antineutrino source within a cone of half-aperture ß 18 ffi at the 68% C:L: . We discuss the implications of this result for locating a supernova explosion. 1 Introduction Locating a --source in the sky is of primary importance in the case of galactic supernova (SN) explosions; particularly if the SN is not optically visible, either because it is hidden behind the dust of the galactic disk, or because the light emission follows the neutrino burst by hours or days. In this latter case, an early SN detection and location by neutrinos could allow observation of the evolution of the first optical stages. Several pointing methods have been extensively discusse..