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 The KamLAND Collaboration Physics , 2009, DOI: 10.1103/PhysRevC.81.025807 Abstract: Radioactive isotopes produced through cosmic muon spallation are a background for rare-event detection in $\nu$ detectors, double-$\beta$-decay experiments, and dark-matter searches. Understanding the nature of cosmogenic backgrounds is particularly important for future experiments aiming to determine the pep and CNO solar neutrino fluxes, for which the background is dominated by the spallation production of $^{11}$C. Data from the Kamioka liquid-scintillator antineutrino detector (KamLAND) provides valuable information for better understanding these backgrounds, especially in liquid scintillators, and for checking estimates from current simulations based upon MUSIC, FLUKA, and GEANT4. Using the time correlation between detected muons and neutron captures, the neutron production yield in the KamLAND liquid scintillator is measured to be $(2.8 \pm 0.3) \times 10^{-4} \mu^{-1} g^{-1} cm^{2}$. For other isotopes, the production yield is determined from the observed time correlation related to known isotope lifetimes. We find some yields are inconsistent with extrapolations based on an accelerator muon beam experiment.
 Statistics , 2008, Abstract: The main goal of the KamLAND reactor electron anti-neutrino experiment is a search for electron anti-neutrino oscillation using inverse-beta decay reaction in 1,000 ton of ultra-pure liquid scintillator. The data-set is 1490.8 days from Mar. 2002 to May 2007. The best-fit oscillation parameters are Delta m^{2}_{21} = 7.58^{+0.14}_{-0.13} (stat.) +/- 0.15 (syst.) x 10$^{-5} eV^{2} and tan^{2}theta_{12} = 0.56^{+0.10}_{-0.07} (stat.) ^{+0.10}_{-0.06} (syst.). The statistical significance for reactor electron anti-neutrino disappearance is 8.8 sigma, and an undistorted electron anti-neutrino energy spectrum is disfavored at > 5 sigma.  Jason Detwiler Physics , 2003, Abstract: The Kamioka Liquid-scintillator Anti-Neutrino Detector (KamLAND) has detected for the first time the disappearance of electron antineutrinos from a terrestrial source at the 99.95% C.L. Interpreted in terms of neutrino oscillations, the best fit to the KamLAND data gives a mixing angle 1.0 and a mass-squared difference 6.9 x 10^-5 eV^2, in excellent agreement with the Large Mixing Angle solution to the solar neutrino problem. Assuming CPT invariance, this result excludes other solutions to the solar neutrino problem at > 99.95% C.L.  Atsuto Suzuki Physics , 2014, DOI: 10.1140/epjc/s10052-014-3094-x Abstract: The primary goal of KamLAND is a search for the oscillation of$\bar{\nu}_{\rm e}$$'s emitted from distant power reactors. The long baseline, typically 180 km, enables KamLAND to address the oscillation solution of the solar neutrino problem with \bar{\nu}_{\rm e} under laboratory conditions. KamLAND found fewer reactor \bar{\nu}_{\rm e} events than expected from standard assumptions about \bar{\nu}_{\rm e}$$'$s propagation at more than 9 {\sigma} confidence level (C.L.). The observed energy spectrum disagrees with the expected spectral shape at more than 5 {\sigma} C.L., and prefers the distortion from neutrino oscillation effects. A three-flavor oscillation analysis of the data from KamLAND and KamLAND + solar neutrino experiments with CPT invariance, yields${\Delta}{\rm m}^{2}_{21} = [{7.54}^{+0.19}_{0.18},\ {7.53}^{+0.19}_{0.18}]\times {10}^{-5} {\rm eV}^{2}$,$\tan^{2} {\theta}_{12} = [{0.481}^{+0.092}_{-0.080},\ {0.437}^{+0.029}_{-0.026}]$, and${\sin}^{2} {\theta}_{13} = [{0.010}^{+0.033}_{-0.034},{0.023}^{+0.015}_{-0.015}]$. All solutions to the solar neutrino problem except for the large mixing angle (LMA) region are excluded. KamLAND also demonstrated almost two cycles of the periodic feature expected from neutrino oscillation effects. KamLAND performed the first experimental study of antineutrinos from the Earth$'$s interior so-called geoneutrinos (geo$\bar{\nu}_{\rm e}$$'s), and succeeded in detecting geo \bar{\nu}_{\rm e}$$$s produced by the decays of$^{238}$U and$^{232}$Th within the Earth. Assuming a chondritic Th/U mass ratio, we obtain${116}^{+28}_{-27}\bar{\nu}_{\rm e}$events from$^{238}$U and$^{232}$Th, corresponding a geo$\bar{\nu}_{\rm e}$flux of${3.4}^{+0.8}_{-0.8} \times {10}^{6} {\rm cm}^{-2}{\rm s}^{-1}\$ at the KamLAND location. We evaluate various bulk silicate Earth composition models using the observed geoneutrino rate.