Precision measurement of neutrino oscillation parameters and investigation of nuclear georeactor hypothesis with KamLAND

摘要

A combined analysis of examining the neutrino oscillation parameters and investigation of nuclear georeactor hypothesis with the KamLAND experiement is presented. With a total exposure of 2.75 kton-years, 930 anti-electron-neutrino candidate events above 3.4 MeV neutrino energy threshold were detected, with estimated 109±13 events from backgrounds. Assuming CPT invariance by combining with solar neutrino results, the best-fit value of georeactor fission power is 4.9^(+3.8)_(-4.8) TW. The 90% upper limit on the georeactor power is determined to be 11.2 TW. This result has put a significant constraint on the contribution of a possible georeactor to the total heat from the Earth. The best-fit values of the neutrino oscillation parameters, including the georeactor power as a free parameter, is consistent with KamLAND's previously published results with null-georeactor assumption.