What will the first year of SNO show?

TL;DR

This paper predicts the charged current event ratios in SNO under various neutrino oscillation scenarios, highlighting how measurements can distinguish between no oscillation, active, and sterile neutrino models.

Contribution

It provides detailed predictions of SNO's CC event ratios for multiple neutrino oscillation solutions, including energy dependence and effects of hep flux anomalies.

Findings

Predicted CC ratio ranges for different oscillation models.

Expected event counts above 13 MeV for active solutions.

Significant differences between oscillation scenarios and no-oscillation case.

Abstract

The ratio of the measured to the predicted standard model CC event rates in SNO will be 0.47 if no oscillations occur. The best-fit active oscillation predictions for the CC ratio are: 0.35-39 (MSW) and 0.38-42 (vacuum) (all for a 5 MeV energy threshold), typically about 20% less than the no-oscillation expectation. We calculate the predicted ratios for six active and sterile neutrino oscillation solutions allowed at 99% CL and determine the dependence of the ratios on energy threshold. If the high-energy anomaly observed by SuperKamiokande is due to an enhanced hep flux, MSW active solutions predict that out of a total of 5000 CC events above 5 MeV in SNO between 49 and 54 events will be observed above 13 MeV whereas only 19 events are expected for no-oscillations and a nominal standard hep flux.