4,822 research outputs found
Measurement of neutrino oscillation with KamLAND: Evidence of spectral distortion
We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 v_e candidate events with energies above 3.4 MeV compared to 365.2±23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8±7.3 expected background events, the statistical significance for reactor v_e over bar (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from v_e oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Δm^2=7.9_(-0.5)^(+0.6)x10^(-5) eV^2. A global analysis of data from KamLAND and solar-neutrino experiments yields
Δm^2=7.9_(-0.5)^(+0.6)x10^(-5) eV^2 and tan^2θ=0.40_(-0.07)^(+0.10), the most precise determination to date
High Sensitivity Search for v_e’s from the Sun and Other Sources at KamLAND
Data corresponding to a KamLAND detector exposure of 0.28 kton yr has been used to search for ν̅ _e’s in the energy range 8.3 < E_(ν̅e) < 14.8 MeV. No candidates were found for an expected background of 1.1±0.4 events. This result can be used to obtain a limit on ν̅_e fluxes of any origin. Assuming that all ν̅_e flux has its origin in the Sun and has the characteristic ^8B solar ν_e energy spectrum, we obtain an upper limit of 3.7×10^2 cm^(-2) ^(s-1) (90% C.L.) on the ν̅_e flux. We interpret this limit, corresponding to 2.8×10^(-4) of the standard solar model ^8B ν_e flux, in the framework of spin-flavor precession and neutrino decay models
ZEN2: A narrow J-band search for z~9 Lya emitting galaxies directed towards three lensing clusters
We present the results of a continuing survey to detect Lya emitting galaxies
at redshifts z~9: the ZEN ("z equals nine'') survey. We have obtained deep
VLT/ISAAC observations in the narrow J-band filter NB119 directed towards three
massive lensing clusters: Abell clusters 1689, 1835, and 114. The foreground
clusters provide a magnified view of the distant universe and permit a
sensitive test for the presence of very high-redshift galaxies. We search for
z~9 Lya emitting galaxies displaying a significant narrow-band excess relative
to accompanying J-band observations that remain undetected in HST/ACS optical
images of each field. No sources consistent with this criterion are detected
above the unlensed 90% point-source flux limit of the narrow-band image,
F_NB=3.7e-18 ergs/s/cm2. To date, the total coverage of the ZEN survey has
sampled a volume at z~9 of approximately 1700 co-moving Mpc3 to a Lya emission
luminosity of 1e43 erg/s. We conclude by considering the prospects for
detecting z~9 Lya emitting galaxies in light of both observed galaxy properties
at z7.Comment: 7 pages, MNRAS accepte
Primordialists and Constructionists: a typology of theories of religion
This article adopts categories from nationalism theory to classify theories of religion. Primordialist explanations are grounded in evolutionary psychology and emphasize the innate human demand for religion. Primordialists predict that religion does not decline in the modern era but will endure in perpetuity. Constructionist theories argue that religious demand is a human construct. Modernity initially energizes religion, but subsequently undermines it. Unpacking these ideal types is necessary in order to describe actual theorists of religion. Three distinctions within primordialism and constructionism are relevant. Namely those distinguishing: a) materialist from symbolist forms of constructionism; b) theories of origins from those pertaining to the reproduction of religion; and c) within reproduction, between theories of religious persistence and secularization. This typology helps to make sense of theories of religion by classifying them on the basis of their causal mechanisms, chronology and effects. In so doing, it opens up new sightlines for theory and research
Who Participates in Voluntary Action?
Who would you say are the most active participants in voluntary action programs in your community? The authors examine the WHO portion of that question and present data indicating middle- or higher-income status individuals in the middle of their life cycle with adequate personal health, extensive informal interpersonal relationships, and who are exposed to mass media as those likely to join voluntary associations and action programs. Is this true in your community? Having this type of knowledge and information should give you clues on how you can more effectively reach and recruit more volunteers
A compact ultra-clean system for deploying radioactive sources inside the KamLAND detector
We describe a compact, ultra-clean device used to deploy radioactive sources
along the vertical axis of the KamLAND liquid-scintillator neutrino detector
for purposes of calibration. The device worked by paying out and reeling in
precise lengths of a hanging, small-gauge wire rope (cable); an assortment of
interchangeable radioactive sources could be attached to a weight at the end of
the cable. All components exposed to the radiopure liquid scintillator were
made of chemically compatible UHV-cleaned materials, primarily stainless steel,
in order to avoid contaminating or degrading the scintillator. To prevent radon
intrusion, the apparatus was enclosed in a hermetically sealed housing inside a
glove box, and both volumes were regularly flushed with purified nitrogen gas.
An infrared camera attached to the side of the housing permitted real-time
visual monitoring of the cable's motion, and the system was controlled via a
graphical user interface.Comment: Revised author affiliations, corrected typos, made minor improvements
to text, and revised reference
The detection of back-to-back proton pairs in Charged-Current neutrino interactions with the ArgoNeuT detector in the NuMI low energy beam line
Short range nucleon-nucleon correlations in nuclei (NN SRC) carry important
information on nuclear structure and dynamics. NN SRC have been extensively
probed through two-nucleon knock- out reactions in both pion and electron
scattering experiments. We report here on the detection of two-nucleon
knock-out events from neutrino interactions and discuss their topological
features as possibly involving NN SRC content in the target argon nuclei. The
ArgoNeuT detector in the Main Injector neutrino beam at Fermilab has recorded a
sample of 30 fully reconstructed charged current events where the leading muon
is accompanied by a pair of protons at the interaction vertex, 19 of which have
both protons above the Fermi momentum of the Ar nucleus. Out of these 19
events, four are found with the two protons in a strictly back-to-back high
momenta configuration directly observed in the final state and can be
associated to nucleon Resonance pionless mechanisms involving a pre-existing
short range correlated np pair in the nucleus. Another fraction (four events)
of the remaining 15 events have a reconstructed back-to-back configuration of a
np pair in the initial state, a signature compatible with one-body Quasi
Elastic interaction on a neutron in a SRC pair. The detection of these two
subsamples of the collected (mu- + 2p) events suggests that mechanisms directly
involving nucleon-nucleon SRC pairs in the nucleus are active and can be
efficiently explored in neutrino-argon interactions with the LAr TPC
technology
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