602 research outputs found
Unbinned test of time-dependent signals in real-time neutrino oscillation experiments
Real-time neutrino oscillation experiments such as Super-Kamiokande (SK), the
Sudbury Neutrino Observatory (SNO), the Kamioka Liquid scintillator
Anti-Neutrino Detector (KamLAND), and Borexino, can detect time variations of
the neutrino signal, provided that the statistics is sufficiently high. We
quantify this statement by means of a simple unbinned test, whose sensitivity
depends on the variance of the signal in the time domain, as well as on the
total number of signal and background events. The test allows a unified
discussion of the statistical uncertainties affecting current or future
measurements of eccentricity-induced variations and of day-night asymmetries
(in SK, SNO, and Borexino), as well as of reactor power variations (in
KamLAND).Comment: 17 pages, including 3 figure
Neutrino mass and mixing parameters: A short review
We present a brief review of the current status of neutrino mass and mixing
parameters, based on a comprehensive phenomenological analysis of neutrino
oscillation and non-oscillation searches, within the standard three-neutrino
mixing framework.Comment: 11 pages, including 7 figures. Presented at the 40th Rencontres de
Moriond on Electroweak Interactions and Unified Theories, La Thuile, Aosta
Valley, Italy, 5-12 Mar 200
Probing particle and nuclear physics models of neutrinoless double beta decay with different nuclei
Half-life estimates for neutrinoless double beta decay depend on particle
physics models for lepton flavor violation, as well as on nuclear physics
models for the structure and transitions of candidate nuclei. Different models
considered in the literature can be contrasted - via prospective data - with a
"standard" scenario characterized by light Majorana neutrino exchange and by
the quasiparticle random phase approximation, for which the theoretical
covariance matrix has been recently estimated. We show that, assuming future
half-life data in four promising nuclei (Ge-76, Se-82, Te-130, and Xe-136), the
standard scenario can be distinguished from a few nonstandard physics models,
while being compatible with alternative state-of-the-art nuclear calculations
(at 95% C.L.). Future signals in different nuclei may thus help to discriminate
at least some decay mechanisms, without being spoiled by current nuclear
uncertainties. Prospects for possible improvements are also discussed.Comment: Minor corrections in the text, references added. Matches published
version in Phys. Rev. D 80, 015024 (2009
Mantle geoneutrinos in KamLAND and Borexino
The KamLAND and Borexino experiments have observed, each at ~4 sigma level,
signals of electron antineutrinos produced in the decay chains of thorium and
uranium in the Earth's crust and mantle (Th and U geoneutrinos). Various pieces
of geochemical and geophysical information allow an estimation of the crustal
geoneutrino flux components with relatively small uncertainties. The mantle
component may then be inferred by subtracting the estimated crustal flux from
the measured total flux. To this purpose, we analyze in detail the experimental
Th and U geoneutrino event rates in KamLAND and Borexino, including neutrino
oscillation effects. We estimate the crustal flux at the two detector sites,
using state-of-the-art information about the Th and U distribution on global
and local scales. We find that crust-subtracted signals show hints of a
residual mantle component, emerging at ~2.4 sigma level by combining the
KamLAND and Borexino data. The inferred mantle flux slightly favors scenarios
with relatively high Th and U abundances, within +-1 sigma uncertainties
comparable to the spread of predictions from recent mantle models.Comment: Slight changes and improvements in the text & figures. Results
unchanged. To appear in Phys. Rev.
LESSONS ON OROGRAPHIC PRECIPITATION FROM MAP
Although moisture-laden airflow towards a mountain is a necessary ingredient, the results from MAP taught us that detailed knowledge of the orographically modified flow is crucial for predicting the intensity, location and duration of orographic precipitation. Understanding the orographically modified flow as it occurs in the Alps was difficult since it depends on the static stability of the flow, which is heavily influenced by the complex effects of latent heating, and the mountain shape, which has important and complicated variations on scales ranging from a few to 100\u27s of kilometers. Central themes in all the wet-MAP studies are the ways the complex Alpine orography influenced the moist, stratified airflow to produce the observed precipitation patterns, by determining the location and
rate of upward air motion and triggering fine-scale motions and microphysical processes that locally enhance the growth and fallout of precipitation. In this presentation will review the major findings from the MAP observations, along with related theoretical developments
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