339 research outputs found
Leptonic CP violation studies at MiniBooNE in the (3+2) sterile neutrino oscillation hypothesis
We investigate the extent to which leptonic CP-violation in (3+2) sterile
neutrino models leads to different oscillation probabilities for
and oscillations at
MiniBooNE. We are using a combined analysis of short-baseline (SBL) oscillation
results, including the LSND and null SBL results, to which we impose additional
constraints from atmospheric oscillation data. We obtain the favored regions in
MiniBooNE oscillation probability space for both (3+2) CP-conserving and (3+2)
CP-violating models. We further investigate the allowed CP-violation phase
values and the MiniBooNE reach for such a CP violation measurement. The
analysis shows that the oscillation probabilities in MiniBooNE neutrino and
antineutrino running modes can differ significantly, with the latter possibly
being as much as three times larger than the first. In addition, we also show
that all possible values of the single CP-violation phase measurable at short
baselines in (3+2) models are allowed within 99% CL by existing data.Comment: Fixed a typo following PRD Erratum. 8 pages, 5 figure
Social technologies for online learning: theoretical and contextual issues
Three exemplars are presented of social technologies deployed in educational contexts: wikis; a photo-sharing environment; and a social bookmarking tool. Students were found to engage with the technologies selectively, sometimes rejecting them, in the light of their prior conceptions of education. Some students (a minority in all the studies) were unsympathetic to the educational philosophy underpinning the technology’s adoption. The paper demonstrates, through an examination of in-context use, the importance of socio-cultural factors in relation to education, and the non-deterministic nature of educational technology. The academic study of technology has increasingly called into question the deterministic views which are so pervasive in popular discourse and among policy makers. Instead, socio-cultural factors play a crucial role in shaping and defining technology and educational technology is no exception, as the examples in the paper show. The paper concludes by drawing out some implications of the examples for the use of social technologies in education
MiniBooNE and LSND data: non-standard neutrino interactions in a (3+1) scheme versus (3+2) oscillations
The recently observed event excess in MiniBooNE anti-neutrino data is in
agreement with the LSND evidence for electron anti-neutrino appearance. We
propose an explanation of these data in terms of a (3+1) scheme with a sterile
neutrino including non-standard neutrino interactions (NSI) at neutrino
production and detection. The interference between oscillations and NSI
provides a source for CP violation which we use to reconcile different results
from neutrino and anti-neutrino data. Our best fit results imply NSI at the
level of a few percent relative to the standard weak interaction, in agreement
with current bounds. We compare the quality of the NSI fit to the one obtained
within the (3+1) and (3+2) pure oscillation frameworks. We also briefly comment
on using NSI (in an effective two-flavour framework) to address a possible
difference in neutrino and anti-neutrino results from the MINOS experiment.Comment: 28 pages, 9 figures, discussion improved, new appendix added,
conclusions unchange
Probing Sterile Neutrino Parameters with Double Chooz, Daya Bay and RENO
In this work, we present a realistic analysis of the potential of the
present-day reactor experiments Double Chooz, Daya Bay and RENO for probing the
existence of sterile neutrinos. We present exclusion regions for sterile
oscillation parameters for each of these experiments, using simulations with
realistic estimates of systematic errors and detector resolutions, and compare
the sterile parameter sensitivity regions we obtain with the existing bounds
from other reactor experiments. We find that these experimental set-ups give
significant bounds on the parameter \Theta_{ee} especially in the low sterile
oscillation region 0.01 < \Delta m_{41}^2 < 0.05 eV^2. These bounds can add to
our understanding of the sterile neutrino sector since there is still a tension
in the allowed regions from different experiments for sterile parameters.Comment: 12 pages, 5 figure
Measurement of inclusive charged current interactions on carbon in a few-GeV neutrino beam
The SciBooNE Collaboration reports a measurement of inclusive charged current
interactions of muon neutrinos on carbon with an average energy of 0.8 GeV
using the Fermilab Booster Neutrino Beam. We compare our measurement with two
neutrino interaction simulations: NEUT and NUANCE. The charged current
interaction rates (product of flux and cross section) are extracted by fitting
the muon kinematics, with a precision of 6-15% for the energy dependent and 3%
for the energy integrated analyses. We also extract CC inclusive interaction
cross sections from the observed rates, with a precision of 10-30% for the
energy dependent and 8% for the energy integrated analyses. This is the first
measurement of the CC inclusive cross section on carbon around 1 GeV. These
results can be used to convert previous SciBooNE cross section ratio
measurements to absolute cross section values.Comment: 21 pages, 16 figures. Accepted by Phys. Rev. D. Minor revisions to
match the accepted versio
Renaissance of the ~1 TeV Fixed-Target Program
This document describes the physics potential of a new fixed-target program
based on a ~1 TeV proton source. Two proton sources are potentially available
in the future: the existing Tevatron at Fermilab, which can provide 800 GeV
protons for fixed-target physics, and a possible upgrade to the SPS at CERN,
called SPS+, which would produce 1 TeV protons on target. In this paper we use
an example Tevatron fixed-target program to illustrate the high discovery
potential possible in the charm and neutrino sectors. We highlight examples
which are either unique to the program or difficult to accomplish at other
venues.Comment: 31 pages, 11 figure
Search for Charged Current Coherent Pion Production on Carbon in a Few-GeV Neutrino Beam
The SciBooNE Collaboration has performed a search for charged current
coherent pion production from muon neutrinos scattering on carbon, \nu_\mu
^{12}C \to \mu^- ^{12}C \pi^+, with two distinct data samples. No evidence for
coherent pion production is observed. We set 90% confidence level upper limits
on the cross section ratio of charged current coherent pion production to the
total charged current cross section at 0.67\times 10^{-2} at mean neutrino
energy 1.1 GeV and 1.36\times 10^{-2} at mean neutrino energy 2.2 GeV.Comment: 18 pages, 16 figures, Minor revisions to match version accepted for
publication in Physical Review
Cosmological parameters constraints from galaxy cluster mass function measurements in combination with other cosmological data
We present the cosmological parameters constraints obtained from the
combination of galaxy cluster mass function measurements (Vikhlinin et al.,
2009a,b) with new cosmological data obtained during last three years: updated
measurements of cosmic microwave background anisotropy with Wilkinson Microwave
Anisotropy Probe (WMAP) observatory, and at smaller angular scales with South
Pole Telescope (SPT), new Hubble constant measurements, baryon acoustic
oscillations and supernovae Type Ia observations.
New constraints on total neutrino mass and effective number of neutrino
species are obtained. In models with free number of massive neutrinos the
constraints on these parameters are notably less strong, and all considered
cosmological data are consistent with non-zero total neutrino mass \Sigma m_\nu
\approx 0.4 eV and larger than standard effective number of neutrino species,
N_eff \approx 4. These constraints are compared to the results of neutrino
oscillations searches at short baselines.
The updated dark energy equation of state parameters constraints are
presented. We show that taking in account systematic uncertainties, current
cluster mass function data provide similarly powerful constraints on dark
energy equation of state, as compared to the constraints from supernovae Type
Ia observations.Comment: Accepted for publication in Astronomy Letter
Learning Objects, Learning Objectives and Learning Design.
Educational research and development into e-learning mainly focuses on the inclusion of new technological features without taking into account psycho-pedagogical concerns that are likely to improve a learner's cognitive process in this new educational category. This paper presents an instructional model that combines objectivist and constructivist learning theories. The model is based on the concept of a learning objective which is composed of a set of learning objects. A software tool, called the Instruction Aid System (IAS), has been developed to guide instructors through the development of learning objectives and the execution of the analysis and design phases of the proposed instructional model. Additionally, a blended approach to the learning process in Web-based distance education is also presented. This approach combines various event-based activities: self-paced learning, live e-learning and the use of face-to-face contact in classrooms
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