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G. P. Zeller

Publications and source records attributed to G. P. Zeller.

At least 55 records · Page 3Linked to original sources

Expression of Interest for Neutrinos Scattering on Glass: NuSOnG

We propose a 3500 ton (3000 ton fiducial volume) SiO_2 neutrino detector with sampling calorimetry, charged particle tracking, and muon spectrometers to run in a Tevatron Fixed Target Program. Improvements to the Fermilab accelerator complex should allow substantial increases in the neutrino flux over the previous NuTeV quad triplet beamline. With 4E19 protons on target/year, a 5 year run would achieve event statistics more than 100 times higher than NuTeV. With 100 times the statistics of previous high energy neutrino experiments, the purely weak processes [ν_μ e^- \to ν_μ+ e^-] and [ν_μ e^- \to ν_e + μ^-] (inverse muon decay) can be measured with high accuracy for the first time. The inverse muon decay process is independent of strong interaction effects and can be used to significantly improve the flux normalization for all other processes. The high neutrino and antineutrino fluxes also make new searches for lepton flavor violation and neutral heavy leptons possible. In this document, we give a first look at the physics opportunities, detector and beam design, and calibration procedures.

hep-ex↗

First Measurement of $ν_μ$ and $ν_e$ Events in an Off-Axis Horn-Focused Neutrino Beam

We report the first observation of off-axis neutrino interactions in the MiniBooNE detector from the NuMI beamline at Fermilab. The MiniBooNE detector is located 745 m from the NuMI production target, at 110 mrad angle ($6.3^{\circ}$) with respect to the NuMI beam axis. Samples of charged current quasi-elastic $ν_μ$ and $ν_e$ interactions are analyzed and found to be in agreement with expectation. This provides a direct verification of the expected pion and kaon contributions to the neutrino flux and validates the modeling of the NuMI off-axis beam.

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Measurement of the ν_μcharged current π^+ to quasi-elastic cross section ratio on mineral oil in a 0.8 GeV neutrino beam

Using high statistics samples of charged current $ν_μ$ interactions, MiniBooNE reports a measurement of the single charged pion production to quasi-elastic cross section ratio on mineral oil (CH$_2$), both with and without corrections for hadron re-interactions in the target nucleus. The result is provided as a function of neutrino energy in the range 0.4 GeV $< E_ν<$ 2.4 GeV with 11% precision in the region of highest statistics. The results are consistent with previous measurements and the prediction from historical neutrino calculations.

hep-ex↗

A Review of Target Mass Corrections

With recent advances in the precision of inclusive lepton--nuclear scattering experiments, it has become apparent that comparable improvements are needed in the accuracy of the theoretical analysis tools. In particular, when extracting parton distribution functions in the large-x region, it is crucial to correct the data for effects associated with the nonzero mass of the target. We present here a comprehensive review of these target mass corrections (TMC) to structure functions data, summarizing the relevant formulas for TMCs in electromagnetic and weak processes. We include a full analysis of both hadronic and partonic masses, and trace how these effects appear in the operator product expansion and the factorized parton model formalism, as well as their limitations when applied to data in the x->1 limit. We evaluate the numerical effects of TMCs on various structure functions, and compare fits to data with and without these corrections.

hep-ph↗

First Observation of Coherent $π^0$ Production in Neutrino Nucleus Interactions with $E_ν<$ 2 GeV

The MiniBooNE experiment at Fermilab has amassed the largest sample to date of $π^0$s produced in neutral current (NC) neutrino-nucleus interactions at low energy. This paper reports a measurement of the momentum distribution of $π^0$s produced in mineral oil (CH$_2$) and the first observation of coherent $π^0$ production below 2 GeV. In the forward direction, the yield of events observed above the expectation for resonant production is attributed primarily to coherent production off carbon, but may also include a small contribution from diffractive production on hydrogen. Integrated over the MiniBooNE neutrino flux, the sum of the NC coherent and diffractive modes is found to be (19.5 $\pm$1.1 (stat) $\pm$2.5 (sys))% of all exclusive NC $π^0$ production at MiniBooNE. These measurements are of immediate utility because they quantify an important background to MiniBooNE's search for $ν_μ \to ν_e$ oscillations.

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Precise Measurement of Neutrino and Anti-neutrino Differential Cross Sections

The NuTeV experiment at Fermilab has obtained a unique high statistics sample of neutrino and anti-neutrino interactions using its high-energy sign-selected beam. We present a measurement of the differential cross section for charged-current neutrino and anti-neutrino scattering from iron. Structure functions, F_2(x,Q^2) and xF_3(x,Q^2), are determined by fitting the inelasticity, y, dependence of the cross sections. This measurement has significantly improved systematic precision as a consequence of more precise understanding of hadron and muon energy scales.

hep-ex↗

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.

hep-ex↗

A Proposal for a Near Detector Experiment on the Booster Neutrino Beamline: FINeSSE: Fermilab Intense Neutrino Scattering Scintillator Experiment

Understanding the quark and gluon substructure of the nucleon has been a prime goal of both nuclear and particle physics for more than thirty years and has led to much of the progress in strong interaction physics. Still the flavor dependence of the nucleon's spin is a significant fundamental question that is not understood. Experiments measuring the spin content of the nucleon have reported conflicting results on the amount of nucleon spin carried by strange quarks. Quasi-elastic neutrino scattering, observed using a novel detection technique, provides a theoretically clean measure of this quantity. The optimum neutrino beam energy needed to measure the strange spin of the nucleon is 1 GeV. This is also an ideal energy to search for neutrino oscillations at high $Δm^2$ in an astrophysically interesting region. Models of the r-process in supernovae which include high-mass sterile neutrinos may explain the abundance of neutron-rich heavy metals in the universe. These high-mass sterile neutrinos are outside the sensitivity region of any previous neutrino oscillation experiments. The Booster neutrino beamline at Fermilab provides the world's highest intensity neutrino beam in the 0.5-1.0 GeV energy range, a range ideal for both of these measurements. A small detector located upstream of the MiniBooNE detector, 100 m from the recently commissioned Booster neutrino source, could definitively measure the strange quark contribution to the nucleon spin. This detector, in conjunction with the MiniBooNE detector, could also investigate $ν_μ$ disappearance in a currently unexplored, cosmologically interesting region.

hep-ex↗

Low Energy Neutrino Cross Sections: Comparison of Various Monte Carlo Predictions to Experimental Data

Charged and neutral current low energy neutrino cross section predictions from a variety of Monte Carlo generators in present use are compared against existing experimental data. Comparisons are made to experimental data on quasi-elastic, resonant and coherent single pion production, multiple pion production, single kaon production, and total inclusive cross sections, and are restricted to the case of muon neutrino scattering off free nucleons.

hep-ex↗

A Departure from Prediction: Electroweak Physics at Nutev

The NuTeV experiment has performed precision measurements of the ratio of neutral-current to charged-current cross-sections in high rate, high energy neutrino and anti-neutrino beams on a dense, primarily steel, target. The separate neutrino and anti-neutrino beams, high statistics, and improved control of other experimental systematics, allow the determination of electroweak parameters with significantly greater precision than past neutrino-nucleon scattering experiments. Our null hypothesis test of the standard model prediction measures sin2thetaW=0.2277+/-0.0013(stat)+/-0.0009(syst), a value which is 3.0 standard deviations above the prediction. We discuss possible explanations for and implications of this discrepancy.

hep-ex↗

On the Effect of Asymmetric Strange Seas and Isospin-Violating Parton Distribution Functions on sin2thetaW Measured at NuTeV

The NuTeV collaboration recently reported a value of sin2thetaW measured in neutrino-nucleon scattering that is 3 standard deviations above the standard model prediction. This result is derived assuming that (1) the strange sea is quark-antiquark symmetric, s(x)=sbar(x), and (2) up and down quark distributions are symmetric under the simultaneous interchange of u<->d and p<->n. We report the impact of violations of these symmetries on sin2thetaW and discuss the theoretical and experimental constraints on such asymmetries.

hep-ex↗

A Precise Determination of Electroweak Parameters in Neutrino-Nucleon Scattering

The NuTeV collaboration has extracted sin^2theta_W from the ratios of neutral current to charged current neutrino and anti-neutrino cross-sections. Our value, sin^2theta_W(on-shell)=0.2277+/-0.0013(stat)+/-0.0009(syst), is three standard deviations above the standard model prediction. We also present a model independent analysis of the same data.

hep-ex↗

Off the Mass Shell: Electroweak Physics at NuTeV

The NuTeV collaboration has performed precision measurements of the ratio of neutral current to charged current cross-sections in high rate, high energy neutrino and anti-neutrino beams on a dense, primarily steel, target. The separate neutrino and anti-neutrino beams, high statistics, and improved control of other experimental systematics, allow the determination of electroweak parameters with significantly greater precision than past neutrino-nucleon scattering experiments. Our null hypothesis test of the standard model prediction measures sin2thetaW=0.2277+/-0.0013(stat)+/-0.0009(syst), a value which is 3 sigma above the prediction. We discuss possible explanations for and implications of this discrepancy.

hep-ex↗

Reply to the Comment on "A Precise Determination of Electroweak Parameters in Neutrino-Nucleon Scattering"

In a recent comment, Miller and Thomas assert that differences in nuclear shadowing effects between neutrino neutral current (NC) and charged current (CC) interactions could explain the difference between NuTeV's measurement of the weak mixing angle and the prediction from other electroweak data. We argue that the proposed effect could have only a small impact on sin2thetaW derived from the Paschos-Wolfenstein R- and that such an effect is strongly disfavored by the neutrino and anti-neutrino NC-to-CC cross-section ratios also measured by NuTeV.

hep-ex↗

Electroweak Results from NuTeV

The NuTeV collaboration has extracted the electroweak parameter, $\stw$, from the measurement of the ratios of neutral current to charged current neutrino and antineutrino deep inelastic scattering interactions. We find that our measurement, while in agreement with previous neutrino electroweak measurements, is not consistent with the prediction from global electroweak fits. To facilitate interpretation of the result, a model independent analysis is presented and possible explanations are discussed

hep-ex↗

A Search for Muon-neutrino to Electron-neutrino and Muon-antineutrino to Electron-antineutrino Oscillations at NuTeV

Limits on $ν_μ\to ν_e$ and $\barν_μ\to \barν_e$ oscillations are extracted using the NuTeV detector with sign-selected $ν_μ$ and $\nub_μ$ beams. In $\nub_μ$ mode, for the case of $\sin^2 2α= 1$, $Δm^2 > 2.6$ ${\rm eV^2}$ is excluded, and for $Δm^2 \gg 1000$ ${\rm eV^2}$, $\sin^2 2α> 1.1 \times 10^{-3}$. The NuTeV data exclude the high $Δm^2$ end of $\barν_μ\to \barν_e$ oscillations parameters favored by the LSND experiment without the need to assume that the oscillation parameters for $ν$ and $\nub$ are the same. We present the most stringent experimental limits for $ν_μ(\barν_μ) \to ν_e (\barν_e)$ oscillations in the large $Δm^2$ region.

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