Electron Energy Spectra, Fluxes, and Day-Night Asymmetries of B Solar Neutrinos from the 391-Day Salt Phase SNO Data Set

SNO collaboration - arXiv preprint nucl-ex/0502021, 2005 - arxiv.org
SNO collaboration
arXiv preprint nucl-ex/0502021, 2005•arxiv.org
Results are reported from the complete salt phase of the Sudbury Neutrino Observatory
experiment in which NaCl was dissolved in the D $ _2 $ O target. The addition of salt
enhanced the signal from neutron capture, as compared to the pure D $ _2 $ O detector. By
making a statistical separation of charged-current events from other types based on event-
isotropy criteria, the effective electron recoil energy spectrum has been extracted. In units of
$10^ 6$ cm $^{-2} $ s $^{-1} $, the total flux of active-flavor neutrinos from $^ 8$ B decay in …
Results are reported from the complete salt phase of the Sudbury Neutrino Observatory experiment in which NaCl was dissolved in the DO target. The addition of salt enhanced the signal from neutron capture, as compared to the pure DO detector. By making a statistical separation of charged-current events from other types based on event-isotropy criteria, the effective electron recoil energy spectrum has been extracted. In units of cm s, the total flux of active-flavor neutrinos from B decay in the Sun is found to be and the integral flux of electron neutrinos for an undistorted B spectrum is ; the signal from (,e) elastic scattering is equivalent to an electron-neutrino flux of . These results are consistent with those expected for neutrino oscillations with the so-called Large Mixing Angle parameters, and also with an undistorted spectrum. A search for matter-enhancement effects in the Earth through a possible day-night asymmetry in the charged-current integral rate is consistent with no asymmetry. Including results from other experiments, the best-fit values for two-neutrino mixing parameters are eV and degrees.
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