Detecting the upturn of the solar 8 B neutrino spectrum with LENA

The Sudbury Neutrino Observatory is a 1000 T D2O Cerenkov detector that is sensitive to 8 B and hep solar neutrinos. Both Charged Current and Neutral Current interaction rates on deuterons as well as the Elastic Scattering interaction rate on electrons can be measured simultaneously. Assuming an undistorted 8 B neutrino spectrum, the total flux measured with the NC reaction is [Formula: see text], which is consistent with solar models. The νe component of the 8 B solar flux is [Formula: see text] for a kinetic energy threshold of 5 MeV. The non-νe component is [Formula: see text], which is 5.3σ greater than zero, giving strong evidence for solar νe flavor transformation. The Day-Night Asymmetry for the Charged Current interaction is [Formula: see text]. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the νe asymmetry is found to be [Formula: see text]. Combined with other solar neutrino data, a global MSW oscillation analysis strongly favors the Large Mixing Angle (LMA) solution.

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NEUTRINO SPECTRUM DISTORTION DUE TO OSCILLATIONS AND ITS BBN EFFECT

International Journal of Modern Physics D ◽

10.1142/s0218271804004906 ◽

2004 ◽

Vol 13 (05) ◽

pp. 831-841 ◽

Cited By ~ 9

Author(s):

DANIELA KIRILOVA

Keyword(s):

Sterile Neutrino ◽

Big Bang ◽

Neutrino Energy ◽

Electron Neutrino ◽

Initial Population ◽

Neutrino Mixing ◽

Big Bang Nucleosynthesis ◽

Cosmological Constraints ◽

Neutrino Spectrum ◽

Primordial Abundance

We study the distortion of electron neutrino energy spectrum due to oscillations with the sterile neutrino νe↔νs, for different initial populations of the sterile state δNs at the onset of oscillations. The influence of this spectrum distortion on Big Bang Nucleosynthesis is analyzed. Only the case of an initially empty sterile state was studied in previous publications. The primordial abundance of 4He is calculated for all possible δNs:0≤δNs≤1 in the model of oscillations, effective after electron neutrino decoupling, for which the spectrum distortion effects on the neutron–proton transitions are the strongest. It is found that the spectrum distortion effect may be dominant, not only in the case of small δNs, but also in the case of large initial population of νs. For example, in the resonant case it may play a considerable role even for very large δNs~0.8. Cosmological constraints on neutrino mixing for small δNs are discussed.

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THE SOLAR NEUTRINO PROBLEM AND BOUNDS ON SOLAR NEUTRINO FLUXES

Modern Physics Letters A ◽

10.1142/s0217732395001460 ◽

1995 ◽

Vol 10 (19) ◽

pp. 1331-1349 ◽

Cited By ~ 2

Author(s):

WAIKWOK KWONG ◽

S.P. ROSEN

Keyword(s):

Lower Bound ◽

Solar Neutrino ◽

Solar Physics ◽

Current Status ◽

Empirical Methods ◽

Solar Neutrino Problem ◽

Neutrino Spectrum ◽

Theoretical Predictions ◽

Neutrino Fluxes ◽

Semi Empirical

We review the current status of the solar neutrino problem. A survey of the experiments and their results are given, and solar physics crucial to the understanding of these results are discussed. Semi-empirical methods are used to derive bounds on the fluxes of the three most important components (pp, 7Be and 8B) of the solar neutrino spectrum. The 8B neutrinos are directly measured to be about half of the theoretical prediction. Relative to their theoretical predictions, we find the 7Be neutrinos to be highly suppressed and the pp neutrinos not suppressed. We are also able to derive a lower bound on the pp flux.

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