Measurement of the Rate ofνe+d→p+p+e−Interactions Produced byB8Solar Neutrinos at the Sudbury Neutrino Observatory

Abstract

Solar neutrinos from ${}^{8}\mathrm{B}$ decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of ${\ensuremath{\nu}}_{e}$'s is measured by the CC reaction rate to be ${\ensuremath{\varphi}}^{\mathrm{CC}}({\ensuremath{\nu}}_{e})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.75\ifmmode\pm\else\textpm\fi{}0.07(\mathrm{stat}{)}_{\ensuremath{-}0.11}^{+0.12}(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.05(\mathrm{theor})\ifmmode\times\else\texttimes\fi{}{10}^{6}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$. Comparison of ${\ensuremath{\varphi}}^{\mathrm{CC}}({\ensuremath{\nu}}_{e})$ to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a $3.3\ensuremath{\sigma}$ difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non- ${\ensuremath{\nu}}_{e}$ component in the solar flux. The total flux of active ${}^{8}\mathrm{B}$ neutrinos is determined to be $5.44\ifmmode\pm\else\textpm\fi{}0.99\ifmmode\times\else\texttimes\fi{}{10}^{6}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$.