AWhat changed
Using heavy water, the SNO Collaboration separated charged-current, neutral-current and elastic-scattering contributions from solar boron-8 neutrinos. Assuming the standard boron-8 spectrum, it inferred a non-electron active-neutrino flux of 3.41 × 10⁶ cm⁻² s⁻¹, reported as 5.3σ above zero, providing strong evidence for flavor transformation.
Scientific scope
Using heavy water, the SNO Collaboration separated charged-current, neutral-current and elastic-scattering contributions from solar boron-8 neutrinos. Assuming the standard boron-8 spectrum, it inferred a non-electron active-neutrino flux of 3.41 × 10⁶ cm⁻² s⁻¹, reported as 5.3σ above zero, providing strong evidence for flavor transformation. The result uses 306.4 live days from the pure heavy-water phase, a 5 MeV reconstructed electron-energy threshold, Monte Carlo response models and measured radioactive backgrounds. The 5.3σ result assumes the standard boron-8 spectral shape; the spectrum-unconstrained neutral-current flux has a larger uncertainty. The neutral-current signal measures total active flavors, without separately resolving muon and tau neutrinos. Adding Super-Kamiokande data changes the reported significance and is not the standalone SNO result.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. The result uses 306.4 live days from the pure heavy-water phase, a 5 MeV reconstructed electron-energy threshold, Monte Carlo response models and measured radioactive backgrounds. The 5.3σ result assumes the standard boron-8 spectral shape; the spectrum-unconstrained neutral-current flux has a larger uncertainty. The neutral-current signal measures total active flavors, without separately resolving muon and tau neutrinos. Adding Super-Kamiokande data changes the reported significance and is not the standalone SNO result.
Contributors
- The named authors in the research record · SCIENCE: Credit belongs to the cited collaborations. The individual author list is incomplete; no sole discoverer or individual effort share is inferred.
Provisional WRS assessment, edition 2026-10-28.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.
Full scientific record · Browse contribution grades · Request a correction