Independent Measurement of the Total Active 8B Solar Neutrino Flux Using an Array of 3He Proportional Counters at the Sudbury Neutrino Observatory

TL;DR

This paper reports a new independent measurement of the total active 8B solar neutrino flux using 3He proportional counters at SNO, confirming previous results and refining neutrino oscillation parameters.

Contribution

It introduces a novel detection technique with 3He counters for measuring the total active neutrino flux, independent of previous methods.

Findings

Total active 8B neutrino flux measured as 5.54 x 10^6 cm^-2 s^-1

Neutrino oscillation parameters refined: Delta m^2 and theta

Uncertainty on mixing angle reduced compared to previous results

Abstract

The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (nu_x) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54(+0.33/-0.31 stat, +0.36/-0.34 syst) x 10^6 cm^-2 s^-1, in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Delta m^2 = 7.59(+0.19/-0.21) x 10^-5 eV^2 and theta = 34.4(+1.3/-1.2) degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results.