Measurement of the Solar Neutrino Flux with an Array of Neutron Detectors in the Sudbury Neutrino Observatory

TL;DR

This paper reports the measurement of the $^8$B solar neutrino flux using an array of neutron detectors at the Sudbury Neutrino Observatory, employing advanced statistical methods to improve the precision of neutrino oscillation parameters.

Contribution

It introduces a novel measurement of the solar neutrino flux with neutron detectors and applies a Markov-Chain Monte-Carlo analysis for enhanced parameter estimation.

Findings

Measured neutrino fluxes consistent with previous results

Improved precision on solar neutrino mixing angle

Confirmed neutrino oscillation model predictions

Abstract

The Sudbury Neutrino Observatory has measured the $^8$B solar neutrino flux using an array of 3He proportional counters. Results obtained using a Markov-Chain Monte-Carlo (MCMC) parameter estimation, integrating over a standard extended likelihood, yield effective neutrino fluxes of: phi_nc=5.54+0.33-0.31(stat)+0.36-0.34(syst) x 10^6 /cm^2/s, phi_cc=1.67+0.05-0.04(stat)+0.07-0.08(syst) x 10^6 /cm^2/s, and phi_es=1.77+0.24-0.21(stat)+0.09-0.10(syst) x 10^6 /cm^2/s. These measurements are in agreement with previous solar neutrino flux measurements, and with neutrino oscillation model results. Including these flux measurements in a global analysis of solar and reactor neutrino results yields an improved precision on the solar neutrino mixing angle of theta=34.4+1.3-1.2 degrees, and Delta m^2=7.59+0.19-0.21 eV^2.