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The NuSOnG experiment is a possible future high-statistics, high-energy neutrino scattering experiment with the potential to make much improved electroweak and QCD measurements using neutrinos as probes. The experiment would use a high-energy external proton beam prossibly at Fermilab or CERN to produce the high-intensity neutrino beam. Studies[2] have been made of the sensitivity of such an experiment to make much improved electroweak measurements associated with νμ — electron elastic scattering and νμ neutral current scattering. These studies show that NuSOnG would be uniquely sensitive to new physics sources such as heavy Z bosons, extended Higgs models, and anomalous neutrino couplings with mass scales up to 4 to 5 TeV. As shown in Ref. [2], these measurements would be complementary to new physics searches at the LHC.

The MiniBooNE Collaboration has reported first results of a search for νe appearance in a νμ beam. With two largely independent analyses, no significant excess was observed of events above background for reconstructed neutrino energies above 475 MeV and the data are consistent with no oscillations within a two neutrino appearance-only oscillation model. An excess of events (186 ± 27 ± 33 events) is observed below the 475 MeV oscillation search cut. This low-energy excess cannot be explained by a two-neutrino oscillation model. This report presents an overview of the MiniBooNE first result and decribes some initial cross checks and investigations associated with the low energy excess.

The MicroBooNE experiment searched for an excess of electron-neutrinos in the Booster Neutrino Beam (BNB), providing direct constraints on \\(\\nu_e\\)-interpretations of the MiniBooNE low-energy excess (LEE). In this article, we show that if the MiniBooNE LEE is caused instead by an excess of \\(\\overline{\\nu}_e\\), then liquid argon detectors, such as MicroBooNE, SBND and ICARUS, would have poor sensitivity to it. This is due to a strong suppression of \\(\\overline{\\nu}_e -{}^{40}\\)Ar cross sections in the low-energy region of the excess. The MicroBooNE results are consistent at the \\(2\\sigma\\)~C.L with a scenario in which the MiniBooNE excess is sourced entirely by \\(\\overline{\\nu}_e\\) interactions. The opportune location of ANNIE, a Gd-loaded water Cherenkov detector, allows for a direct search for a \\(\\overline{\\nu}_e\\) flux excess in the BNB using inverse-beta-decay events.

We revisit models of heavy neutral leptons (neutrissimos) with transition magnetic moments as explanations of the \\(4.8\\sigma\\) excess of electron-like events at MiniBooNE. We perform a detailed Monte Carlo-based analysis to re-examine the preferred regions in the model parameter space to explain MiniBooNE, considering also potential contributions from oscillations due to an eV-scale sterile neutrino. We then derive robust constraints on the model using neutrino-electron elastic scattering data from MINERvA. We find that MINERvA rules out a large region of parameter space, but allowed solutions exist at the \\(2\\sigma\\) confidence level. A dedicated MINERvA analysis would likely be able to probe the entire region of preference of MiniBooNE in this model.

The electron-like excess observed by the MiniBooNE experiment is explained with a model comprising a new low mass state (\\(\\mathcal{O}(1)\\) eV) participating in neutrino oscillations and a new high mass state (\\(\\mathcal{O}(100)\\) MeV) that decays to \\(\\nu+\\gamma\\). Short-baseline oscillation data sets are used to predict the oscillation parameters. Fitting the MiniBooNE energy and scattering angle data, there is a narrow joint allowed region for the decay contribution at 95% CL. The result is a substantial improvement over the single sterile neutrino oscillation model, with \\(\\Delta \\chi^2/dof\\) = 19.3/2 for a decay coupling of \\(2.8 \\times 10^{-7}\\) GeV\\(^{-1}\\), high mass state of 376 MeV, oscillation mixing angle of \\(7\\times 10^{-4}\\) and mass splitting of \\(1.3\\) eV\\(^2\\). This model predicts that no clear oscillation signature will be observed in the FNAL short baseline program due to the low signal-level.

The IsoDAR sterile-neutrino search requires a very high intensity neutrino source. For IsoDAR, this high intensity is produced using the high neutron flux from a 60 MeV, 10 mA proton beam striking a beryllium target that floods a sleeve of highly-enriched Li-7. Through neutron capture the Li-7 is transmuted to Li-8, which beta-decays giving the desired high neutrino flux for very-short baseline neutrino experiments. The target can be placed very close to can existing large neutrino detector, which is typically located deep underground to reduce backgrounds. With such a setup, it is necessary to design a shielding enclosure for the target to prevent neutrons from causing unacceptable activation of the rock walls close to the target. Various materials have been studied including steel to thermalize the high energy neutrons and two new types of concrete developed by Jefferson Laboratory, one very light with shredded plastic aggregate, and the other one enriched with high quantities of boron. The shielding is asymmetrical, having a larger thickness towards the detector in order to suppress the neutron and gamma background in the neutrino detector. Simulation results for rock activation and for detector backgrounds are presented.

This report explores the results and implications of the weak mixing angle measurement made by the NuTeV neutrino experiment at Fermilab. The NuTeV experiment, using a technique that exploits muon neutrino and antineutrino data to determine the neutral current to charged current ratios, Rν and ${\\rm R}^{\\bar{\\nu}}$, has made the most precise measurement of the weak mixing angle using neutrinos as probes. The result gives a valueof sin2θw(on − shell) = 0.2277 ± 0.0016 which is about three standard deviations larger than the standard model prediction of 0.2227. Various interpretations for the source of the anomaly are considered including changes to the inputs to the standard model predictions, unexpected symmetry violations, or new physios interpretations involving unanticipated neutrino properties or new particle contributions. Speculations on new precison measurements to further explore this region are also presented, including, for example, a future reactor neutrino-electron elastic scattering measurement. At present the discrepancy is unexplained, but could point to some as yet undiscovered broken quark symmetry, or towaids new physics associated with neutrino interactions or mixings.

This paper reviews the results of the LSND and MiniBooNE experiments. The primary goal of each experiment was to effect sensitive searches for neutrino oscillations in the mass region with \\(\\Delta m^2 \\sim 1\\) eV\\(^2\\). The two experiments are complementary, and so the comparison of results can bring additional information with respect to models with sterile neutrinos. Both experiments obtained evidence for \\(\\bar \\nu_\\mu \\rightarrow \\bar \\nu_e\\) oscillations, and MiniBooNE also observed a \\(\\nu_\\mu \\rightarrow \\nu_e\\) excess. In this paper, we review the design, analysis, and results from these experiments. We then consider the results within the global context of sterile neutrino oscillation models. The final data sets require a more extended model than the simple single sterile neutrino model imagined at the time that LSND drew to a close and MiniBooNE began. We show that there are apparent incompatibilities between data sets in models with two sterile neutrinos. However, these incompatibilities may be explained with variations within the systematic error. Overall, models with two (or three) sterile neutrinos seem to succeed in fitting the global data, and they make interesting predictions for future experiments.

We investigate how the data from various future neutrino oscillation experiments will constrain the physics parameters for a three active neutrino mixing model. The investigations properly account for the degeneracies and ambiguities associated with the phenomenology as well as estimates of experimental measurement errors. Combinations of various reactor measurements with the expected J-PARC (T2K) and NuMI offaxis (Nova) data, both with and without the increased flux associated with proton driver upgrades, are considered. The studies show how combinations of reactor and offaxis data can resolve degeneracies (e.g. the theta23 degeneracy) and give more precise information on the oscillation parameters. A primary purpose of this investigation is to establish the parameter space regions where CP violation can be discovered and where the mass hierarchy can be determined. It is found that such measurements, even with the augmented flux from proton driver upgrades, demand sin^2 (2 theta13) be fairly large and in the range where it is measurable by reactor experiments.

Neutrino scattering measurements offer a unique tool to probe the electroweak and strong interactions as described by the Standard Model (SM). Electroweak measurements are accessible through the comparison of neutrino neutral- and charged-current scattering. These measurements are complimentary to other electroweak measurements due to differences in the radiative corrections both within and outside the SM. Neutrino scattering measurements also provide a precise method for measuring the F_2(x,Q^2) and xF_3(x,Q^2 structure functions. The predicted Q^2 evolution can be used to test perturbative Quantum Chromodynamics as well as to measure the strong coupling constant, alpha _s, and the valence, sea, and gluon parton distributions. In addition, neutrino charm production, which can be determined from the observed dimuon events, allows the strange-quark sea to be investigated along with measurements of the CKM matrix element |V_{cd}| and the charm quark mass.