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UBC Theses and Dissertations

Through-going muons at the Sudbury Neutrino Observatory Tsui, Tyron


This thesis presents results from the through-going muon analysis at the Sudbury Neutrino Observatory. Over 1229.26 days, 77376 direct cosmic ray muons above cosθ > 0.4 and 514 neutrino-induced muons in the range -1 < cosθ < 0.4 were detected. A log-likelihood analysis was performed on the neutrino-induced muons to produce a flux measurement and constrain atmospheric neutrino mixing parameters. The best-fit oscillation values were Δm² = (2.6±2.0) × 10⁻³ eV², sin²2θ = 1.0±0.1. The observed muon flux was found to be (2.48±0.25) × 10⁻¹³ cm⁻²s⁻¹sr⁻¹ resulting in an overall flux normalization 1.22±0.09 times the theoretical estimates from the Bartol group. The quoted uncertainties are 1-D marginalized. The no-oscillation hypothesis was ruled out at 99.8% confidence level. The observed number of direct cosmic ray muons was converted into a vertical depth intensity. The resulting fits to the intensity as a function of depth were I₀ = (0.93±0.05) × 10⁻⁶ cm⁻²s⁻¹sr⁻¹, x = 2.33±0.31 km.w.e. and α = 5.62±0.40.

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