Reactor on-off antineutrino measurement with KamLAND

Abstract

The recent long-term shutdown of Japanese nuclear reactors has resulted in a significantly reduced reactor νe flux at KamLAND. This running condition provides a unique opportunity to confirm and constrain backgrounds for the reactor νe oscillation analysis. The data set also has improved sensitivity for other νe signals, in particular νe's produced in β-decays from 238 U and 232 Th within the Earth's interior, whose energy spectrum overlaps with that of reactor νe's. Including constraints on θ13 from accelerator and short-baseline reactor neutrino experiments, a combined three-flavor analysis of solar and KamLAND data gives fit values for the oscillation parameters of tan 2 θ12 = 0.436

Search for the proton decay modep→ν¯K+with KamLAND

“…KamLAND is the largest scintillation detector constructed to date, with a detector mass of 1 kton [12]. As discussed in Ref.…”

Spectroscopy of geoneutrinos from 2056 days of Borexino data

“…A negligible amount of correlated events with a ∼1 s time constant were identified and their contribution in theν e time window determined. (3) (α,n) background for ν e search has been extensively discussed elsewhere [3][4][5][6][7]. The average rate of 210 Po in the dataset is determined to be (14.1±0.2) counts/(day·ton).…”

KamLAND: geo-neutrino measurement in Japan

“…After the publication of the KamLAND result in Gando et al [2013], new reference models with refined crustal compositions become available in the literature. If the reference model [Enomoto et al 2007] used in the analysis in Gando et al [2013] is replaced with a modern model [Huang et al 2013], the radiogenic heat is estimated to be 14.9 +9.8 −8.3 TW from U and Th.…”

“…If the reference model [Enomoto et al 2007] used in the analysis in Gando et al [2013] is replaced with a modern model [Huang et al 2013], the radiogenic heat is estimated to be 14.9 +9.8 −8.3 TW from U and Th. The increase of the radiogenic heat estimation is mainly due to the change in the crustal geo o − e flux contribution, which is the offset of the flux-heat conversion function as shown in Figure 4.…”