High Sensitivity Anti-neutrino Detection by Kamland

Electron anti-neutrinos (ν̄e) from nuclear power reactors have been observed by KamLAND. Data from 0.16 kton·year exposure (145.1 live days) indicates disappearance of ν̄e at 99.95% C.L. in the energy range 2.6 MeV < Eν̄e < 8.0 MeV. Considering two-flavor neutrino oscillation with CPT invariance, the only remaining solution to the solar neutrino problem is the Large Mixing Angle (LMA) solution. In addition a 0.28kton·year exposure (185.5 live days) was searched for ν̄e in the energy range 8.3 MeV < Eν̄e < 14.8 MeV. No candidate events were found with expected background of 1.1±0.4 events. Assuming that the origin of ν̄e in this energy region comes from B solar νe, we find an upper limit of νe to ν̄e conversion probability of 2.8 ×10.