Title: Beyond Fluxes with the Sudbury Neutrino Observatory


In the past few years, the Sudbury Neutrino Observatory has demonstrated that the total active flux of neutrinos observed is consistent with the standard solar model prediction although there is a suppression in the number of electron neutrinos observed from the sun. The Mikheev-Smirnov-Wolfenstein model, which is used to describe the observed electron neutrino suppression, also predicts a distortion in the neutrino energy spectrum and/or a difference in electron neutrino survival probability day versus night. Neither of these outcomes has been observed. Additionally, certain models of non-standard interactions also predict a distortion of the neutrino energy spectrum. This talk discusses the physics potential of a spectral measurement to test these predictions and focuses on the experimental challenge of lowering the analysis energy threshold in SNO in order to be more sensitive to observing spectral distortions.