| Electron flavoured neutrinos are produced in the solar core and oscillate into the muon and tau flavours according to the MSW mechanism. This theory predicts that the oscillation is enhanced by the passage through matter. As a consequence, passage through the earth can cause the regeneration of electron flavoured neutrinos. Solar neutrino experiments are expected to detect an asymmetry between the day and night electron neutrino flux, with a greater number of νe present when the sun is below the horizon.; The Sudbury Neutrino Observatory is a large underground heavy water Čerenkov detector. This thesis examines the data from SNO for the presence of a day/night asymmetry in &phis;e. Using the results from 254 days of NaCl salt-injected operation, the day/night asymmetry was found to be Ae=0.045± stat+0.026-0.024 syst ; where the positive value indicates a greater flux during the night.; This result is statistically-limited but is in good agreement with previous experimental measurements from SNO and Super-Kamiokande, and with theoretical predictions based upon the current values of neutrino oscillation parameters. |
