SNO+ Results

Reactor Antineutrino Oscillations

Simplified fit prompt energy spectrum of reactor antineutrino IBD events

Fit prompt energy spectra from Measurement of Reactor Antineutrino Oscillations with 1.46 Kilotonne-Years of Data at SNO+ (Phys. Rev. Lett. 137, 101807 (2026)). Shown above is the fit reactor IBD spectrum with the background-subtracted data, from the fit with the oscillation parameters unconstrained.

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Fit prompt energy spectra

The fit spectra from the paper, with the “No Reactor osc.” line removed. The (α, n)-IBD classifier separates (α, n) backgrounds from IBD events.

Fit prompt energy spectrum, oscillation parameters unconstrained — **Unconstrained:** oscillation parameters unconstrained, no (α, n)-IBD classifier. PDF

Fit prompt energy spectrum, oscillation parameters constrained to PDG2025 — **Constrained:** oscillation parameters constrained to PDG2025 priors, no (α, n)-IBD classifier. PDF

Fit prompt energy spectrum, constrained, with the (alpha, n)-IBD classifier — **Constrained with classifier:** oscillation parameters constrained to PDG2025 priors, (α, n)-IBD classifier used. PDF

Simplified spectra

Simplified versions of the unconstrained fit, suitable for thumbnails and small figures. They show the fit reactor IBD spectrum and the background-subtracted data.

Simplified spectrum, reactor IBD combined — **Combined:** all reactor IBD contributions as one spectrum. PDF

Simplified spectrum, reactor IBD split into three contributions — **Separated:** reactor IBD split into, from top to bottom, Bruce, Pickering + Darlington, and the rest of the world. PDF

Partial Fill ROI

Liquid scintillator background characterisation for the neutrinoless double beta decay region of interest (ROI) for the SNO+ partial fill, when the detector was filled with 365 tonnes of liquid scintillator (LAB + 0.6 g/L PPO) on top of 479 tonnes of ultrapure water.

SNO+ Water Phase External Backgrounds

Distribution of external background events from the SNO+ water phase as a function of reconstructed radius and u·r, where u·r is the dot product between the reconstructed event direction and the radial vector.