8 research outputs found
Measurement of Neutrino Oscillation with KamLAND: Evidence of Spectral Distortion
We present results of a study of neutrino oscillation based on a 766 ton-year
exposure of KamLAND to reactor anti-neutrinos. We observe 258 \nuebar\
candidate events with energies above 3.4 MeV compared to 365.2 events expected
in the absence of neutrino oscillation. Accounting for 17.8 expected background
events, the statistical significance for reactor \nuebar disappearance is
99.998%. The observed energy spectrum disagrees with the expected spectral
shape in the absence of neutrino oscillation at 99.6% significance and prefers
the distortion expected from \nuebar oscillation effects. A two-neutrino
oscillation analysis of the KamLAND data gives \DeltaMSq =
7.9 eV. A global analysis of data from KamLAND
and solar neutrino experiments yields \DeltaMSq =
7.9 eV and \ThetaParam =
0.40, the most precise determination to date.Comment: 5 pages, 4 figures; submitted to Phys.Rev.Letter
First Results from KamLAND: Evidence for Reactor Anti-Neutrino Disappearance
KamLAND has been used to measure the flux of 's from distant
nuclear reactors. In an exposure of 162 tonyr (145.1 days) the ratio of
the number of observed inverse -decay events to the expected number of
events without disappearance is for energies 3.4 MeV. The deficit of events is
inconsistent with the expected rate for standard propagation at
the 99.95% confidence level. In the context of two-flavor neutrino oscillations
with CPT invariance, these results exclude all oscillation solutions but the
`Large Mixing Angle' solution to the solar neutrino problem using reactor
sources.Comment: 6 pages, 6 figure
First Results from KamLAND: Evidence for Reactor Antineutrino Disappearance
KamLAND has been used to measure the flux of 's from distant nuclear reactors. In an exposure of 162 tonyr (145.1 days) the ratio of the number of observed inverse -decay events to the expected number of events without disappearance is for energies 3.4 MeV. The deficit of events is inconsistent with the expected rate for standard propagation at the 99.95% confidence level. In the context of two-flavor neutrino oscillations with CPT invariance, these results exclude all oscillation solutions but the `Large Mixing Angle' solution to the solar neutrino problem using reactor sources
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Measurement of neutrino oscillation with Kamland: Evidence of spectral distortion
Recent status of the KamLAND experiment
The KamLAND experiment is a very long baseline reactor ̄ne oscillation experiment. This experiment has sensitivity to the oscillation parameters Δℳ2 > 10-5 eV2 and sin2θ > 0.2, using reactor ̄ne which come typically from 170km away. This sensitive region completely covers the currently most favored MSW-LMA solution for the solar neutrino deficit problem. After 5 years of detector construction, the data taking started successfully in Jan. 2002. The detector performance is sufficient to perform reactor ̄ne physics and we expect the first physics result will come out soon. In this paper, the KamLAND detector, its expected sensitivities, history, and recent progress since the time of the conference, are briefly described
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Measurement of neutrino oscillation with Kamland: Evidence of spectral distortion
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First results from KamLAND: Evidence for reactor anti-neutrino disappearance
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