Abstract
We observed, for the first time, solar neutrinos in the 1.0–1.5 MeV energy range. We determined the rate of solar neutrino interactions in Borexino to be . Assuming the neutrino flux predicted by the standard solar model, we obtained a constraint on the CNO solar neutrino interaction rate of ( C.L.). The absence of the solar neutrino signal is disfavored at C.L., while the absence of the signal is disfavored at C.L. The necessary sensitivity was achieved by adopting data analysis techniques for the rejection of cosmogenic , the dominant background in the 1–2 MeV region. Assuming the Mikheyev-Smirnov-Wolfenstein large mixing angle solution to solar neutrino oscillations, these values correspond to solar neutrino fluxes of and ( C.L.), respectively, in agreement with both the high and low metallicity standard solar models. These results represent the first direct evidence of the neutrino signal and the strongest constraint of the CNO solar neutrino flux to date.
- Received 14 October 2011
DOI:https://doi.org/10.1103/PhysRevLett.108.051302
© 2012 American Physical Society
Synopsis
Rare Fusion Reactions Probed with Solar Neutrinos
Published 2 February 2012
An underground neutrino detector has found the first evidence of a nuclear reaction that produces deuterium in the sun.
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