What can the SNO Neutral Current Rate teach us about the Solar Neutrino Anomaly

Abstract

We investigate how the anticipated neutral current rate from $SNO$ will sharpen our understanding of the solar neutrino anomaly. Quantitative analyses are performed with representative values of this rate in the expected range of $0.8-1.2$. This would provide a $5-10\sigma$ signal for ${\nu }_e$ transition into a state containing an active neutrino component. Assuming this state to be purely active one can estimate both the ${}^{8}B$ neutrino flux and the ${\nu }_e$ survival probability to a much higher precision than currently possible. Finally the measured value of the $NC$ rate will have profound implications for the mass and mixing parameters of the solar neutrino oscillation solution.

Comments: Brief discussion on the first NC result from SNO added; final version to be published in the MPLA