Measurements of the Solar Neutrino Flux from Super-Kamiokande's First 300 Days

TL;DR

This paper reports the initial measurements of solar neutrino flux by Super-Kamiokande over 300 days, confirming a flux level significantly below theoretical predictions and demonstrating flux stability over time.

Contribution

First measurement of solar neutrino flux by Super-Kamiokande using recoil electrons above 6.5 MeV, confirming previous results and providing new data on flux stability.

Findings

Measured flux of 2.42×10^6/cm^2/s, 36% of BP95 model prediction

Flux consistent over 1.5 month intervals

Results align with Kamiokande measurements

Abstract

The first results of the solar neutrino flux measurement from Super-Kamiokande are presented. The results shown here are obtained from data taken between the 31st of May, 1996, and the 23rd of June, 1997. Using our measurement of recoil electrons with energies above 6.5 MeV, we infer the total flux of 8B solar neutrinos to be 2.42+-0.06(stat.)+0.10-0.07(syst.)*10^6/cm^2/s. This result is consistent with the Kamiokande measurement and is 36% of the flux predicted by the BP95 solar model. The flux is also measured in 1.5 month subsets and shown to be consistent with a constant rate.