11,525 research outputs found
Confronting the short-baseline oscillation anomalies with a single sterile neutrino and non-standard matter effects
We examine the MiniBooNE neutrino, MiniBooNE antineutrino and LSND
antineutrino data sets in a two-neutrino
oscillation approximation subject to non-standard matter effects. We assume
those effects can be parametrized by an -independent effective potential,
, experienced only by an intermediate, non-weakly-interacting
(sterile) neutrino state which we assume participates in the oscillation, where
corresponds to neutrino/antineutrino propagation. We discuss the
mathematical framework in which such oscillations arise in detail, and derive
the relevant oscillation probability as a function of the vacuum oscillation
parameters and , and the matter effect
parameter . We are able to successfully fit all three data sets, including
the MiniBooNE low energy excess, with the following best-fit model parameters:
eV, , and
eV. The -probability for the best fit
corresponds to 21.6%, to be compared to 6.8% for a fit where has been set
to zero, corresponding to a (3+1) sterile neutrino oscillation model. We find
that the compatibility between the three data sets corresponds to 17.4%, to be
compared to 2.3% for . Finally, given the fit results, we examine
consequences for reactor, solar, and atmospheric oscillations. For this paper,
the presented model is empirically driven, but the results obtained can be
directly used to investigate various phenomenological interpretations such as
non-standard matter effects.Comment: 19 pages, 11 figures, 1 tabl
Can a 3+2 Oscillation Model Explain the NuTeV Electroweak Results?
The weak mixing angle result from NuTeV falls three standard deviations above
the value determined by global electroweak fits. It has been suggested that one
possible explanation for this result could be the oscillation of electron
neutrinos in the NuTeV beam to sterile neutrinos. This article examines several
cases of masses and mixings for 3+2 neutrino oscillation models which fit the
current oscillation data at 99% CL. We conclude that electron to sterile
neutrino oscillations can account for only up to a third of a standard
deviation between the NuTeV determination of the weak mixing angle and the
standard model.Comment: 3 pages, 2 figures, submitted to Brief Report
Sterile Neutrino Fits to Short Baseline Neutrino Oscillation Measurements
This paper reviews short baseline oscillation experiments as interpreted
within the context of one, two, and three sterile neutrino models associated
with additional neutrino mass states in the ~1 eV range. Appearance and
disappearance signals and limits are considered. We show that fitting short
baseline data sets to a (3+3) model, defined by three active and three sterile
neutrinos, results in an overall goodness of fit of 67%, and a compatibility of
90% among all data sets -- to be compared to the compatibility of 0.043% and
13% for a (3+1) and a (3+2) model, respectively. While the (3+3) fit yields the
highest quality overall, it still finds inconsistencies with the MiniBooNE
appearance data sets; in particular, the global fit fails to account for the
observed MiniBooNE low-energy excess. Given the overall improvement, we
recommend using the results of (3+2) and (3+3) fits, rather than (3+1) fits,
for future neutrino oscillation phenomenology. These results motivate the
pursuit of further short baseline experiments, such as those reviewed in this
paper.Comment: Submitted to Advances in High Energy Physics Special Issue on
Neutrino Physic
Anode-Coupled Readout for Light Collection in Liquid Argon TPCs
This paper will discuss a new method of signal read-out from photon detectors
in ultra-large, underground liquid argon time projection chambers. In this
design, the signal from the light collection system is coupled via capacitive
plates to the TPC wire-planes. This signal is then read out using the same
cabling and electronics as the charge information. This greatly benefits light
collection: it eliminates the need for an independent readout, substantially
reducing cost; It reduces the number of cables in the vapor region of the TPC
that can produce impurities; And it cuts down on the number of feed-throughs in
the cryostat wall that can cause heat-leaks and potential points of failure. We
present experimental results that demonstrate the sensitivity of a LArTPC wire
plane to photon detector signals. We also simulate the effect of a 1 s
shaping time and a 2 MHz sampling rate on these signals in the presence of
noise, and find that a single photoelectron timing resolution of 30 ns
can be achieved.Comment: 16 pages, 15 figure
Improved TPB-coated Light Guides for Liquid Argon TPC Light Detection Systems
Scintillation light produced in liquid argon (LAr) must be shifted from 128
nm to visible wavelengths in light detection systems used for liquid argon
time-projection chambers (LArTPCs). To date, LArTPC light collection systems
have employed tetraphenyl butadiene (TPB) coatings on photomultiplier tubes
(PMTs) or plates placed in front of the PMTs. Recently, a new approach using
TPB-coated light guides was proposed. In this paper, we report on light guides
with improved attenuation lengths above 100 cm when measured in air. This is an
important step in the development of meter-scale light guides for future
LArTPCs. Improvements come from using a new acrylic-based coating,
diamond-polished cast UV transmitting acrylic bars, and a hand-dipping
technique to coat the bars. We discuss a model for connecting bar response in
air to response in liquid argon and compare this to data taken in liquid argon.
The good agreement between the prediction of the model and the measured
response in liquid argon demonstrates that characterization in air is
sufficient for quality control of bar production. This model can be used in
simulations of light guides for future experiments.Comment: 25 pages, 20 figure
Identifying Robust Milk Production Systems
The European dairy industry faces an increasingly uncertain world. There is uncertainty about subsidy payment levels and compliance conditions, global competition, price variability, consumer demand, carbon footprints, water quality, biodiversity, landscapes, animal welfare, food safety, etc. The future is uncertain because it cannot be reliably predicted; therefore the industry must adopt production systems that will be financially robust over a wide range of possible circumstances. Adding to the uncertainty is a lack of consensus regarding the specific characteristics of these sustainable production systems. In this interdisciplinary research project we developed a profit maximizing whole-farm model and employ it to identify robust milk production systems for Northern Ireland under varying market, policy and farm family conditions. The milk production systems incorporated into the model involve variations in date of calving, quantity of concentrate fed, and nature of forage utilized. The model also incorporates a disaggregated specification of time use within farm households and links intra-household resource allocation to the process of agricultural technology adoption. This work illustrates how profit maximizing whole-farm models can play a decision support role in helping farmers, agricultural researchers, agribusiness advisers and agricultural policy makers to identify economically sustainable agricultural production systems.Production Economics,
Effects of noise upon human information processing
Studies of noise effects upon human information processing are described which investigated whether or not effects of noise upon performance are dependent upon specific characteristics of noise stimulation and their interaction with task conditions. The difficulty of predicting noise effects was emphasized. Arousal theory was considered to have explanatory value in interpreting the findings of all the studies. Performance under noise was found to involve a psychophysiological cost, measured by vasoconstriction response, with the degree of response cost being related to scores on a noise annoyance sensitivity scale. Noise sensitive subjects showed a greater autonomic response under noise stimulation
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