391 research outputs found
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A letter of intent for a neutrino scattering experiment on the booster neutrino meanline: FINeSSE
The experiment described in this Letter of Intent provides a decisive measurement of {Delta}s, the spin of the nucleon carried by strange quarks. This is crucial as, after more than thirty years of study, the spin contribution of strange quarks to the nucleon is still not understood. The interpretation of {Delta}s measurements from inclusive Deep Inelastic Scattering (DIS) experiments using charged leptons suffers from two questionable techniques; an assumption of SU(3)-flavor symmetry, and an extrapolation into unmeasured kinematic regions, both of which provide ample room for uncertain theoretical errors in the results. The results of recent semi-inclusive DIS data from HERMES paint a somewhat different picture of the contribution of strange quarks to the nucleon spin than do the inclusive results, but since HERMES does not make use of either of the above-mentioned techniques, then the results are somewhat incomparable. What is required is a measurement directly probing the spin contribution of the strange quarks in the nucleon. Neutrino experiments provide a theoretically clean and robust method of determining {Delta}s by comparing the neutral current interaction, which is isoscalar plus isovector, to the charged current interaction, which is strictly isovector. A past experiment, E734, performed at Brookhaven National Laboratory, has pioneered this effort. Building on what they have learned, we present an experiment which achieves a measurement to {+-} 0.025 using neutrino scattering, and {+-} 0.04 using anti-neutrino scattering, significantly better than past measurements. The combination of the neutrino and anti-neutrino data, when combined with the results of the parity-violating electron-nucleon scattering data, will produce the most significant result for {Delta}s. This experiment can also measure neutrino cross sections in the energy range required for accelerator-based precision oscillation measurements. Accurate measurements of cross sections have been identified as a priority of the neutrino community, as determined through the APS Multidisciplinary Study on the Future of Neutrino Physics. From the APS report, the Neutrino Matrix makes its recommendations in context of several assumptions regarding the neutrino program, including: ''Determination of the neutrino reaction and production cross sections required for a precise understanding of neutrino oscillation physics and the neutrino astronomy of astrophysical and cosmological sources. Our broad and exacting program of neutrino physics is built upon precise knowledge of how neutrinos interact with matter''. The experiment described here will provide unique information on cross sections of {approx}1 GeV neutrinos, in precisely the range explored by present and future long baseline oscillation programs. Fermi National Accelerator Laboratory is the natural place to perform this experiment. The physics goals proposed here grow the existing program and are necessary ingredients for the next generation oscillation physics measurements in this same energy range. This is a small, cost-effective, and timely experiment which fits well with the growing neutrino program at Fermilab
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Analysis of the proposed relocation of the neutron criticality clusters in the process buildings for the Portsmouth Gaseous Diffusion Plant
Radiation levels in Buildings X-326, X-330 and X-333 have been determined for the ANSI minimum accident of concern at both the current and the proposed locations of the criticality alum system neutron detectors. This was performed in order to evaluate whether or not the detectors could be lowered from their current positions and still respond to the minimum accident of concern. Relocating the detectors could reduce the potential for worker in injury when the approximately 90-pound alarms need to be removed for periodic maintenance. It could also decrease the incidence of battery failure from elevated temperatures which can exceed 160 degrees F. At the proposed 1-meter elevation the detectors would be surrounded by the cells containing the cascade equipment; therefore, the detectors would be less responsive to a criticality event. The results of this analysis indicate that the detectors could be lowered from their current height of 5 meters to a height of 1 meter and still respond to the minimum accident of concern. This analysis was performed using the MCNP monte carlo code with a source corresponding to a critical system of uranyl fluoride solutions of 1.2, 3.0, and 4.95 weight percent U-235 enrichment. The neutron dose rates were evaluated at positions of 69 meters and 100 meters radially outward from the source at 5 meter and 1 meter heights. All neutron detectors located in the three process buildings are located within 100 meters from any potential criticality. This report details the methodology used for this study, background on the data employed, and a comparison to a similar analysis performed in 1983
Global three-parameter model for neutrino oscillations using Lorentz violation
A model of neutrino oscillations is presented that has only three degrees of
freedom and is consistent with existing data. The model is a subset of the
renormalizable sector of the Standard-Model Extension (SME), and it offers an
alternative to the standard three-neutrino massive model. All classes of
neutrino data are described, including solar, reactor, atmospheric, and LSND
oscillations. The disappearance of solar neutrinos is obtained without
matter-enhanced oscillations. Quantitative predictions are offered for the
ongoing MiniBooNE experiment and for the future experiments OscSNS, NOvA, and
T2K.Comment: 12 pages REVTe
Tests of Lorentz violation in muon antineutrino to electron antineutrino oscillations
A recently developed Standard-Model Extension (SME) formalism for neutrino
oscillations that includes Lorentz and CPT violation is used to analyze the
sidereal time variation of the neutrino event excess measured by the Liquid
Scintillator Neutrino Detector (LSND) experiment. The LSND experiment,
performed at Los Alamos National Laboratory, observed an excess, consistent
with neutrino oscillations, of in a beam of . It
is determined that the LSND oscillation signal is consistent with no sidereal
variation. However, there are several combinations of SME coefficients that
describe the LSND data; both with and without sidereal variations. The scale of
Lorentz and CPT violation extracted from the LSND data is of order
GeV for the SME coefficients and . This solution for
Lorentz and CPT violating neutrino oscillations may be tested by other short
baseline neutrino oscillation experiments, such as the MiniBooNE experiment.Comment: 10 pages, 10 figures, 2 tables, uses revtex4 replaced with version to
be published in Physical Review D, 11 pages, 11 figures, 2 tables, uses
revtex
Neutrino-induced pion production from nuclei at medium energies
We present a fully relativistic formalism for describing neutrino-induced
-mediated single-pion production from nuclei. We assess the ambiguities
stemming from the interactions. Variations in the cross sections of
over 10% are observed, depending on whether or not magnetic-dipole dominance is
assumed to extract the vector form factors. These uncertainties have a direct
impact on the accuracy with which the axial-vector form factors can be
extracted. Different predictions for induce up to 40-50% effects
on the -production cross sections. To describe the nucleus, we turn to
a relativistic plane-wave impulse approximation (RPWIA) using realistic
bound-state wave functions derived in the Hartree approximation to the
- Walecka model. For neutrino energies larger than 1 GeV, we
show that a relativistic Fermi-gas model with appropriate binding-energy
correction produces comparable results as the RPWIA which naturally includes
Fermi motion, nuclear-binding effects and the Pauli exclusion principle.
Including medium modifications yields a 20 to 25% reduction of the
RPWIA cross section. The model presented in this work can be naturally extended
to include the effect of final-state interactions in a relativistic and
quantum-mechanical way. Guided by recent neutrino-oscillation experiments, such
as MiniBooNE and K2K, and future efforts like MINERA, we present ,
, and various semi-inclusive distributions, both for a free nucleon and
carbon, oxygen and iron targets.Comment: 25 pages, 14 figure
The OscSNS White Paper
There exists a need to address and resolve the growing evidence for
short-baseline neutrino oscillations and the possible existence of sterile
neutrinos. Such non-standard particles require a mass of eV/c, far
above the mass scale associated with active neutrinos, and were first invoked
to explain the LSND appearance signal.
More recently, the MiniBooNE experiment has reported a excess of
events in antineutrino mode consistent with neutrino oscillations and with the
LSND antineutrino appearance signal. MiniBooNE also observed a
excess of events in their neutrino mode data. Lower than expected
neutrino-induced event rates using calibrated radioactive sources and nuclear
reactors can also be explained by the existence of sterile neutrinos. Fits to
the world's neutrino and antineutrino data are consistent with sterile
neutrinos at this eV/c mass scale, although there is some tension
between measurements from disappearance and appearance experiments. In addition
to resolving this potential major extension of the Standard Model, the
existence of sterile neutrinos will impact design and planning for all future
neutrino experiments. It should be an extremely high priority to conclusively
establish if such unexpected light sterile neutrinos exist. The Spallation
Neutron Source (SNS) at Oak Ridge National Laboratory, built to usher in a new
era in neutron research, provides a unique opportunity for US science to
perform a definitive world-class search for sterile neutrinos.Comment: This white paper is submitted as part of the SNOWMASS planning
proces
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