Distortion of the 8B electron recoil energy spectrum. The figure shows the ratio, R, of the measured number of electrons to the number expected on the basis of the standard models. Solutions are shown with the standard model fluxes of 8B and hep neutrinos (the approximately horizontal lines) and with the standard hep flux multiplied by factors of 8, 15, and 30 (ratio increases at highest energies). The calculated ratios are shown for three different values of m2 and with sin2 2 = 0.79 in order to illustrate the range of behaviors that result from choosing neutrino parameters. Results similar to this viewgraph are obtained if sin2 2 is allowed to vary over a representative range of the allowed global LMA solutions that are consistent with the average measured event rates. The experimental points show the SuperKamiokande results for 708 days of observations. The bottom line is that the observed spectrum is consistent with the standard model and the LMA predictions below about 13.5 MeV. Above 13.5 MeV, there is some indication of a larger counting rate. On the LMA hypothesis, this must be accounted for by contamination by a large hep contribution or by systematic or statistical uncertainties in the experimental data.
The predicted seasonal dependence of the total event rate with eccentricity removed. The dependence of the -e scattering rate in the SuperKamiokande detector upon the season of the year is shown for a representative range of LMA solutions with variable m2 and sin2 2 = 0.8. In order to isolate the seasonal effect of neutrino oscillations, the effect of the eccentricity of the earth's orbit has been removed. The viewgraph refers to all events above 6.5 MeV. Very little seasonal dependence (beyond that implied by the eccentricity of the earth's orbit) is predicted by the LMA. This prediction is consistent with the observations but the current error bars are huge on this scale, approximately ± 0.02.