Solar B-8 and hep neutrino measurements from 1258 days of Super-Kamiokande data

Abstract

Solar neutrino measurements from 1258 days of data from the Super-Kamiokande detector are presented. The measurements are based on recoil electrons in the energy range 5.0-20.0 MeV. The measured solar neutrino flux is 2.32 +/- 0.03(stat)(+0.08)(-0.07) (syst) x 10(6) cm(-2) s(-1) which is 45.1 +/- 0.5 (stat)(+1.6)(-1.4)(syst)% of that predicted by the BP2000 SSM. The day vs nieht flux asymmetry (Phi (n) - Phi (d)) / Phi (average) is 0.033 +/- 0.022(stat)(+0.013)(-0.012)(syst). The recoil electron energy spectrum is consistent with no spectral distortion. For the hep neutrino flux, we set a 90% C.L. upper limit of 40 x 10(3) cm(-2) s(-1) which is 4.3 times the BP2000 SSM prediction.