Solution to the Solar Neutrino Problem

Mon, 01 Jan 2001 00:00:00 +0000

This landmark paper from the Sudbury Neutrino Observatory (SNO) reports the first direct measurement of the electron-neutrino flux from \(^8B\) solar neutrinos via the charged-current (CC) reaction on deuterium, together with the elastic-scattering (ES) rate.

Key points

The CC reaction rate yields an electron-neutrino flux of
\(\phi^{\rm CC}(\nu_e) = 1.75 \pm 0.07\,({\rm stat})\,^{+0.12}_{-0.11}\,({\rm syst}) \pm 0.05\,({\rm theor}) \times 10^6\,{\rm cm}^{-2}\,{\rm s}^{-1}\).
Comparison with the high-precision Super-Kamiokande ES flux measurement shows a \(3.3\sigma\) difference, providing clear evidence for a non-electron active neutrino component in the solar flux (i.e., neutrino flavor transformation).
The total flux of active \(^8B\) neutrinos is determined to be \(5.44 \pm 0.99 \times 10^6\,{\rm cm}^{-2}\,{\rm s}^{-1}\), in good agreement with solar model predictions.

Published 25 July 2001 in Physical Review Letters. This result was a decisive step in establishing solar neutrino oscillations and contributed to the 2015 Nobel Prize in Physics.

Particle Astrophysics |

Solution to the Solar Neutrino Problem

Key points