Joint analysis of Borexino and SNO solar neutrino data and reconstruction of the survival probability

TL;DR

This paper combines Borexino and SNO solar neutrino data to reconstruct the neutrino survival probability, confirming the standard oscillation pattern and providing a comprehensive energy-dependent analysis.

Contribution

It introduces a likelihood-based method to analyze combined solar neutrino data and reconstruct the survival probability across all energies, enhancing understanding of neutrino oscillations.

Findings

Results align with standard oscillation models

Reconstructed survival probability matches KamLAND data

Uncertainties in survival probability are quantitatively assessed

Abstract

Solar neutrino oscillations are supported by KamLAND's antineutrino measurements, but certain solar neutrino data - the observed shape of the ${}^8$B flux and the difference between day and night counting rates measured in Super-Kamiokande - do not fit well with the ensuing oscillation pattern. Interestingly, other solar neutrino data allow independent tests of the survival probability. Thanks to the new measurements of Borexino at low-energies along with the standard solar model and to the results of SNO at high-energies, four values of the neutrino survival probability are known. We build and study a likelihood based only on these solar neutrino data. The results agree well with the standard oscillation pattern and in particular with KamLAND findings. A related and straightforward procedure permits to reconstruct the survival probability of solar neutrinos and to assess its uncertainties, for all solar neutrino energies.