Measurement of the Solar Neutrino Energy Spectrum Using Neutrino-Electron Scattering

A measurement of the energy spectrum of recoil electrons from solar neutrino scattering in the Super-Kamiokande detector is presented. The results shown here were obtained from 504 days of data taken between 31 May 1996 and 25 March 1998. The shape of the measured spectrum is compared with the expectation for solar ${}^8\mathrm{B}$ 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 ${\chi }^2$ of 25.3 with 15 degrees of freedom, corresponding to a $4.6\%$ confidence level.