Measurement of the solar neutrino energy spectrum using neutrino-electron scattering

TL;DR

This paper reports on the measurement of the solar neutrino energy spectrum via neutrino-electron scattering in Super-Kamiokande, comparing observed data with theoretical expectations for B8 neutrinos over 504 days.

Contribution

It provides the first detailed spectral measurement of solar neutrinos in Super-Kamiokande, including a comparison with expected B8 neutrino spectra accounting for detector effects.

Findings

Spectral shape consistent with B8 neutrino predictions within statistical uncertainties.

Chi-square test indicates a 4.6% confidence level for the spectral match.

Data collected over 504 days enhances the statistical significance of the measurement.

Abstract

A measurement of the energy spectrum of recoil electrons from solar neutrino scattering in the Super--Kamiokande detector is presented. The results shown here are obtained from 504 days of data taken between the 31st of May, 1996 and the 25th of March, 1998. The shape of the measured spectrum is compared with the expectation for solar B8 neutrinos. The comparison takes into account both kinematic and detector related effects in the measurement process. The spectral shape comparison between the observation and the expectation gives a chi-square of 25.3 with 15 degrees of freedom, corresponding to a 4.6% confidence level.