Solar neutrino results in Super-Kamiokande-III

The results of the third phase of the Super-Kamiokande solar neutrino measurement are presented and compared to the first and second phase results. With improved detector calibrations, a full detector simulation, and improved analysis methods, the systematic uncertainty on the total neutrino flux is estimated to be ±2.1%, which is about two thirds of the systematic uncertainty for the first phase of Super-Kamiokande. The observed B8 solar flux in the 5.0 to 20 MeV total electron energy region is 2.32±0.04(stat) ±0.05(sys)×106cm^-2sec^-1 under the assumption of pure electron-flavor content, in agreement with previous measurements. A combined oscillation analysis is carried out using SK-I, II, and III data, and the results are also combined with the results of other solar neutrino experiments. The best-fit oscillation parameters are obtained to be ^sin2θ12=0.30-0.01+0.02(^tan2θ 12=0.42-0.02+0.04) and Δm212=6.2-1.9+1.1×10 ^-5eV2. Combined with KamLAND results, the best-fit oscillation parameters are found to be ^sin2θ12=0.31±0. 01(^tan2θ12=0.44±0.03) and Δm212=7.6±0.2×10^-5eV2. The B8 neutrino flux obtained from global solar neutrino experiments is 5.3±0.2(stat+sys) ×106cm^-2s^-1, while the B8 flux becomes 5.1±0.1(stat+sys)×106cm^-2s^-1 by adding KamLAND results. In a three-flavor analysis combining all solar neutrino experiments, the upper limit of ^sin2θ13 is 0.060 at 95% C.L.. After combination with KamLAND results, the upper limit of ^sin2θ13 is found to be 0.059 at 95% C.L. © 2011 American Physical Society.

Duke Scholars

Author Kate Scholberg Physics

Author Christopher Walter Physics