Search for extraterrestrial antineutrino sources with the KamLAND detector

We present the results of a search for extraterrestrial electron antineutrinos ($\bar{\nu}_{e}$'s) in the energy range $8.3 MeV < E_{\bar{\nu}_{e}} < 31.8 MeV$ using the KamLAND detector. In an exposure of 4.53 kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting an upper limit on the probability of $^{8}$B solar $\nu_{e}$'s converting into $\bar{\nu}_{e}$'s at $5.3 \times 10^{-5}$ (90% C.L.), if we assume an undistorted $\bar{\nu}_{e}$ shape. This limit corresponds to a solar $\bar{\nu}_{e}$ flux of $93 cm^{-2} s^{-1}$ or an event rate of $1.6 events (kton-year)^{-1}$ above the energy threshold $(E_{\bar{\nu}_{e}} > 8.3 MeV)$. The present data also allows us to set more stringent limits on the diffuse supernova neutrino flux and on the annihilation rates for light dark matter particles.Comment: 22 pages, 6 figure

Measurement of the 8B Solar Neutrino Flux with the KamLAND Liquid Scintillator Detector

We report a measurement of the neutrino-electron elastic scattering rate from 8B solar neutrinos based on a 123 kton-day exposure of KamLAND. The background-subtracted electron recoil rate, above a 5.5 MeV analysis threshold is 1.49+/-0.14(stat)+/-0.17(syst) events per kton-day. Interpreted as due to a pure electron flavor flux with a 8B neutrino spectrum, this corresponds to a spectrum integrated flux of 2.77+/-0.26(stat)+/-0.32(syst) x 10^6 cm^-2s^-1. The analysis threshold is driven by 208Tl present in the liquid scintillator, and the main source of systematic uncertainty is due to background from cosmogenic 11Be. The measured rate is consistent with existing measurements and with Standard Solar Model predictions which include matter enhanced neutrino oscillation.Comment: 6 pages, 3 figure

Production of Radioactive Isotopes through Cosmic Muon Spallation in KamLAND

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.Comment: 16 pages, 20 figure

Indication for the disappearance of reactor electron antineutrinos in the Double Chooz experiment

The Double Chooz Experiment presents an indication of reactor electron antineutrino disappearance consistent with neutrino oscillations. A ratio of 0.944 $\pm$ 0.016 (stat) $\pm$ 0.040 (syst) observed to predicted events was obtained in 101 days of running at the Chooz Nuclear Power Plant in France, with two 4.25 GW$_{th}$ reactors. The results were obtained from a single 10 m$^3$ fiducial volume detector located 1050 m from the two reactor cores. The reactor antineutrino flux prediction used the Bugey4 measurement as an anchor point. The deficit can be interpreted as an indication of a non-zero value of the still unmeasured neutrino mixing parameter \sang. Analyzing both the rate of the prompt positrons and their energy spectrum we find \sang = 0.086 $\pm$ 0.041 (stat) $\pm$ 0.030 (syst), or, at 90% CL, 0.015 $<$ \sang $\ <$ 0.16.Comment: 7 pages, 4 figures, (new version after PRL referee's comments

Goishi tea consumption inhibits airway hyperresponsiveness in BALB/c mice

<p>Abstract</p> <p>Background</p> <p>Airway hyperresponsiveness (AHR) is one of the important traits that characterize bronchial asthma. Goishi tea is a post-heating fermented tea that has been reported to have higher free radical scavenging activity. In this study, we evaluated the prophylactic effects of Goishi tea on AHR in BALB/c mice.</p> <p>Results</p> <p>The number of inflammatory cells in BAL fluid was considerably reduced in Goishi tea/<it>Der f </it>and Gallic acid/<it>Der f </it>groups as compared with Tap water/<it>Der f </it>group. Regarding inflammatory cells in BAL, a significant reduction of eosinophils and neutrophils was observed in Goishi tea-treated mice (p < 0.01), as well as in the Gallic acid/<it>Der f </it>group (p < 0.05), as compared with Tap water/<it>Der f </it>group. In asthmatic mice (Tap water/<it>Der f </it>group), the intensity of airway resistance increased simultaneously with the increase in acetylcholine concentration in a dose-dependant way. AHR was significantly inhibited in Goishi tea/<it>Der f </it>and Gallic acid/<it>Der f </it>(p < 0.01) groups as compared with the Tap water/<it>Der f </it>group. Regarding serum specific-IgG₁, significantly lower levels of this antibody were observed in Goishi tea/<it>Der f </it>and Gallic acid/<it>Der f </it>groups as compared with the Tap water/<it>Der f </it>group (p < 0.05). In addition, adiponectin level was significantly higher in the Goishi tea group as compared with the Tap water treated mice (p < 0.01).</p> <p>Conclusions</p> <p>The results suggest that Goishi tea consumption exerted an inhibitory effect on eosinophilic and neutrophilic infiltration in the lung, attenuated the increase in airway resistance and increased the production of adiponectin; thus reducing Der f induced allergic inflammatory process in mice.</p

Titanium dioxide particle – induced goblet cell hyperplasia : association with mast cells and IL-13

BACKGROUND: Inhalation of particles aggravates respiratory symptoms including mucus hypersecretion in patients with chronic airway disease and induces goblet cell hyperplasia (GCH) in experimental animal models. However, the underlying mechanisms remain poorly understood. METHODS: To understand this, the numbers of goblet cells, Muc5ac (+) expressing epithelial cells and IL-13 expressing mast cells were measured in the trachea of sham or TiO(2 )particles – treated rats using periodic acid-Schiff, toluidine blue and immunohistochemical staining. RT-PCR for Muc-1, 2 and 5ac gene transcripts was done using RNA extracted from the trachea. Differential cell count and IL-13 levels were measured in bronchoalveolar lavage (BAL) fluid. In pretreatment groups, cyclophosphamide (CPA) or dexamethasone (DEX) was given before instillation of TiO(2). TiO(2 )treatment markedly increased Muc5ac mRNA expression, and Muc5ac (+) or PAS (+) epithelial cells 48 h following treatment. RESULTS: The concentration of IL-13 in BAL fluids was higher in TiO(2 )treated – rats when compared to those in sham rats (p < 0.05). Pretreatment with cyclophosphamide (CPA) decreased the number of neutrophils and eosinophils in BAL fluid of TiO(2 )treated – rats (p < 0.05), but affected neither the percentage of PAS (+) cells, nor IL-13 levels in the BAL fluids (p > 0.05). In contrast, pretreatment with dexamethasone (DEX) diminished the percentage of PAS (+) cells and the levels of IL-13 (p < 0.05). TiO(2 )treatment increased the IL-13 (+) mast cells (p < 0.05) in the trachea, which was suppressed by DEX (p < 0.05), but not by CPA pretreatment (p > 0.05). In addition there were significant correlations of IL-13 (+) rate of mast cells in the trachea with IL-13 concentration in BAL fluid (p < 0.01) and with the percentage of Muc5ac (+) cells in the sham and TiO(2 )treated rats (p < 0.05). CONCLUSION: In conclusion, TiO(2 )instillation induces GCH and Muc5ac expression, and this process may be associated with increased production of IL-13 by mast cells

Constraints on θ13\theta_{13} from A Three-Flavor Oscillation Analysis of Reactor Antineutrinos at KamLAND

We present new constraints on the neutrino oscillation parameters $/textyen Delta m^{2}_{21}$, $/textyen theta_{12}$, and $/textyen theta_{13}$ from a three-flavor analysis of solar and KamLAND data. The KamLAND data set includes data acquired following a radiopurity upgrade and amounts to a total exposure of 3.49 \textyen times 10^{32} target-proton-year. Under the assumption of {\textyen it CPT} invariance, a two-flavor analysis (/textyen mbox{\textyen theta_{13} = 0}) of the KamLAND and solar data yields the best-fit values \textyen tan^{2} \textyen theta_{12} = 0.444^{+0.036}_{-0.030} and \textyen Delta m^{2}_{21} = 7.50^{+0.19}_{-0.20} \textyen times 10^{-5} ~ {\textyen rm eV}^{2}; a three-flavor analysis with \textyen theta_{13} as a free parameter yields the best-fit values \textyen tan^{2} \textyen theta_{12} = 0.452^{+0.035}_{-0.033}, \textyen Delta m^{2}_{21} = 7.50^{+0.19}_{-0.20} \textyen times 10^{-5} ~ {\textyen rm eV}^{2}, and \textyen sin^{2} \textyen theta_{13} = 0.020^{+0.016}_{-0.016}. This \textyen theta_{13} interval is consistent with other recent work combining the CHOOZ, atmospheric and long-baseline accelerator experiments. We also present a new global \textyen theta_{13} analysis, incorporating the CHOOZ, atmospheric and accelerator data, which indicates \textyen sin^{2} \textyen theta_{13} = 0.009^{+0.013}_{-0.007}. A nonzero value is suggested, but only at the 79\textyen% C.L.Comment: 10 pages, 7 figures. Version as published in PRD. The dChi2-map and prompt energy spectrum for this analysis are available at http://www.awa.tohoku.ac.jp/KamLAND/4th_result_data_release/4th_result_data_release.htm