Search

We report the first measurement of monoenergetic muon neutrino charged current interactions. MiniBooNE has isolated 236 MeV muon neutrino events originating from charged kaon decay at rest ($K^+ \rightarrow \mu^+ \nu_\mu$) at the NuMI beamline absorber. These signal $\nu_\mu$-carbon events are distinguished from primarily pion decay in flight $\nu_\mu$ and $\overline{\nu}_\mu$ backgrounds produced at the target station and decay pipe using their arrival time and reconstructed muon energy. The significance of the signal observation is at the 3.9$\sigma$ level. The muon kinetic energy, neutrino-nucleus energy transfer ($\omega=E_\nu-E_\mu$), and total cross section for these events is extracted. This result is the first known-energy, weak-interaction-only probe of the nucleus to yield a measurement of $\omega$ using neutrinos, a quantity thus far only accessible through electron scattering., Comment: 6 pages, 4 figures

The MiniBooNE experiment at Fermilab reports results from an analysis of $\nu_e$ appearance data from $12.84 \times 10^{20}$ protons on target in neutrino mode, an increase of approximately a factor of two over previously reported results. A $\nu_e$ charged-current quasielastic event excess of $381.2 \pm 85.2$ events ($4.5 \sigma$) is observed in the energy range $200, Comment: Improved some of the figures and improved the correlation between neutrino and antineutrino data

The MiniBooNE-DM collaboration searched for vector-boson mediated production of dark matter using the Fermilab 8 GeV Booster proton beam in a dedicated run with $1.86 \times 10^{20}$ protons delivered to a steel beam dump. The MiniBooNE detector, 490~m downstream, is sensitive to dark matter via elastic scattering with nucleons in the detector mineral oil. Analysis methods developed for previous MiniBooNE scattering results were employed, and several constraining data sets were simultaneously analyzed to minimize systematic errors from neutrino flux and interaction rates. No excess of events over background was observed, leading to a 90\% confidence limit on the dark-matter cross section parameter, $Y=\epsilon^2\alpha_D(m_\chi/m_V)^4 \lesssim10^{-8}$, for $\alpha_D=0.5$ and for dark-matter masses of $0.01, Comment: 6 pages, 7 figures, Version consistent with final PRL

This paper explores the use of $L/E$ oscillation probability distributions to compare experimental measurements and to evaluate oscillation models. In this case, $L$ is the distance of neutrino travel and $E$ is a measure of the interacting neutrino's energy. While comparisons using allowed and excluded regions for oscillation model parameters are likely the only rigorous method for these comparisons, the $L/E$ distributions are shown to give qualitative information on the agreement of an experiment's data with a simple two-neutrino oscillation model. In more detail, this paper also outlines how the $L/E$ distributions can be best calculated and used for model comparisons. Specifically, the paper presents the $L/E$ data points for the final MiniBooNE data samples and, in the Appendix, explains and corrects the mistaken analysis published by the ICARUS collaboration.

High-quality charged current quasielastic scattering data have recently been reported for both muon neutrinos and antineutrinos from several accelerator-based neutrino experiments. Measurements from MiniBooNE were the first to indicate that more complex nuclear effects, now thought to be the result of nucleon pair correlations, may contribute to neutrino quasielastic samples at a much higher significance than previously assumed. These findings are now being tested by $\mathrm{MINER}\ensuremath{\nu}\mathrm{A}$ and other contemporary neutrino experiments. Presented here is a comparison of data from MiniBooNE and $\mathrm{MINER}\ensuremath{\nu}\mathrm{A}$ to a few example parametrizations of these nuclear effects. It has been demonstrated that such effects may bias future measurements of neutrino oscillation parameters, and so this issue continues to press the neutrino community. A comparison of data over a large range of neutrino energies is one approach to exploring the extent to which such nucleon correlations may influence our understanding and subsequent modeling of neutrino quasielastic scattering.

We report a measurement of the flux-averaged neutral-current elastic differential cross section for neutrinos scattering on mineral oil (CH{sub 2}) as a function of four-momentum transferred squared, Q{sup 2}. It is obtained by measuring the kinematics of recoiling nucleons with kinetic energy greater than 50 MeV which are readily detected in MiniBooNE. This differential cross-section distribution is fit with fixed nucleon form factors apart from an axial mass, M{sub A}, that provides a best fit for M{sub A} = 1.39 {+-} 0.11 GeV. Using the data from the charged-current neutrino interaction sample, a ratio of neutral-current to charged-current quasi-elastic cross sections as a function of Q{sup 2} has been measured. Additionally, single protons with kinetic energies above 350 MeV can be distinguished from neutrons and multiple nucleon events. Using this marker, the strange quark contribution to the neutral-current axial vector form factor at Q{sup 2} = 0, {Delta}s, is found to be {Delta}s = 0.08{+-} 0.26.

The first measurements of antineutrino charged-current quasielastic ($\numub$ CCQE, $\numu + N \to \mup + N'$) and neutral-current elastic ($\numub$ NCE, $\numu + N \to \numu + N$) cross sections with $< E_{\bar{\nu}} >$ $, Comment: 6 pages, proceedings for the Eighth International Workshop on Neutrino-Nucleus Neutrino Interactions in the Few-GeV Region

The MiniBooNE experiment at Fermilab reports results from an analysis of ν¯e appearance data from 11.27×10²⁰ protons on target in the antineutrino mode, an increase of approximately a factor of 2 over the previously reported results. An event excess of 78.4±28.5 events (2.8σ) is observed in the energy range 200QEν

The largest sample ever recorded of $\numub$ charged-current quasi-elastic (CCQE, $\numub + p \to \mup + n$) candidate events is used to produce the minimally model-dependent, flux-integrated double-differential cross section $\frac{d^{2}\sigma}{dT_\mu d\uz}$ for $\numub$ incident on mineral oil. This measurement exploits the unprecedented statistics of the MiniBooNE anti-neutrino mode sample and provides the most complete information of this process to date. Also given to facilitate historical comparisons are the flux-unfolded total cross section $\sigma(E_\nu)$ and single-differential cross section $\frac{d\sigma}{d\qsq}$ on both mineral oil and on carbon by subtracting the $\numub$ CCQE events on hydrogen. The observed cross section is somewhat higher than the predicted cross section from a model assuming independently-acting nucleons in carbon with canonical form factor values. The shape of the data are also discrepant with this model. These results have implications for intra-nuclear processes and can help constrain signal and background processes for future neutrino oscillation measurements., Comment: 28 pages, 13 figures. Data release at http://www-boone.fnal.gov/for_physicists/data_release/ccqe_nubar/

A proposal submitted to the FNAL PAC is described to search for light sub-GeV WIMP dark matter at MiniBooNE. The possibility to steer the beam past the target and into an absorber leads to a significant reduction in neutrino background, allowing for a sensitive search for elastic scattering of WIMPs off nucleons or electrons in the detector. Dark matter models involving a vector mediator can be probed in a parameter region consistent with the required thermal relic density, and which overlaps the region in which these models can resolve the muon g-2 discrepancy. Estimates of signal significance are presented for various operational modes and parameter points. The experimental approach outlined for applying MiniBooNE to a light WIMP search may also be applicable to other neutrino facilities.

We propose adding 300 mg/l PPO to the existing MiniBooNE detector mineral oil to increase the scintillation response. This will allow the detection of associated neutrons and increase sensitivity to final-state nucleons in neutrino interactions. This increased capability will enable an independent test of whether the current excess seen in the MiniBooNE oscillation search is signal or background. In addition it will enable other neutrino interaction measurements to be made including a search for the strange-quark contribution to the nucleon spin Delta s and a low-energy measurement of charged-current quasielastic scattering.

The SciBooNE and MiniBooNE collaborations report the results of a νμ disappearance search in the Δ'm2 region of 0.5-40 eV2. The neutrino rate as measured by the SciBooNE tracking detectors is used to constrain the rate at the MiniBooNE Cherenkov detector in the first joint analysis of data from both collaborations. Two separate analyses of the combined data samples set 90% confidence level (CL) limits on νμ disappearance in the 0.5-40 eV2 Δm2 region, with an improvement over previous experimental constraints between 10 and 30 eV2

MiniBooNE anti-neutrino charged-current quasi-elastic (CCQE) data is compared to model predictions. The main background of neutrino-induced events is examined first, where three independent techniques are employed. Results indicate the neutrino flux is consistent with a uniform reduction of $\sim$ 20% relative to the largely uncertain prediction. After background subtraction, the $Q^{2}$ shape of $\numub$ CCQE events is consistent with the model parameter $M_{A}$ = 1.35 GeV determined from MiniBooNE $\numu$ CCQE data, while the normalization is $\sim$ 20% high compared to the same prediction., 6 pages, 4 figures. Proceedings for the NuInt 2011 conference

Using a high-statistics, high-purity sample of {nu}{sub {mu}-}induced charged current, charged pion events in mineral oil (CH{sub 2}), MiniBooNE reports a collection of interaction cross sections for this process. This includes measurements of the CC{pi}{sup +} cross section as a function of neutrino energy, as well as flux-averaged single- and double-differential cross sections of the energy and direction of both the final-state muon and pion. In addition, each of the single-differential cross sections are extracted as a function of neutrino energy to decouple the shape of the MiniBooNE energy spectrum from the results. In many cases, these cross sections are the first time such quantities have been measured on a nuclear target and in the 1 GeV energy range.

Two independent methods are employed to measure the neutrino flux of the anti-neutrino-mode beam observed by the MiniBooNE detector. The first method compares data to simulated event rates in a high purity $\numu$ induced charged-current single $\pip$ (CC1$\pip$) sample while the second exploits the difference between the angular distributions of muons created in $\numu$ and $\numub$ charged-current quasi-elastic (CCQE) interactions. The results from both analyses indicate the prediction of the neutrino flux component of the pre-dominately anti-neutrino beam is over-estimated - the CC1$\pip$ analysis indicates the predicted $\numu$ flux should be scaled by $0.76 \pm 0.11$, while the CCQE angular fit yields $0.65 \pm 0.23$. The energy spectrum of the flux prediction is checked by repeating the analyses in bins of reconstructed neutrino energy, and the results show that the spectral shape is well modeled. These analyses are a demonstration of techniques for measuring the neutrino contamination of anti-neutrino beams observed by future non-magnetized detectors., 15 pages, 7 figures, published in Physical Review D, latest version reflects changes from referee comments

We report a measurement of the flux-averaged neutral-current elastic differential cross section for neutrinos scattering on mineral oil (CH{sub 2}) as a function of four-momentum transferred squared, Q{sup 2}. It is obtained by measuring the kinematics of recoiling nucleons with kinetic energy greater than 50 MeV which are readily detected in MiniBooNE. This differential cross-section distribution is fit with fixed nucleon form factors apart from an axial mass M{sub A} that provides a best fit for M{sub A}=1.39{+-}0.11 GeV. Using the data from the charged-current neutrino interaction sample, a ratio of neutral-current to charged-current quasielastic cross sections as a function of Q{sup 2} has been measured. Additionally, single protons with kinetic energies above 350 MeV can be distinguished from neutrons and multiple nucleon events. Using this marker, the strange quark contribution to the neutral-current axial vector form factor at Q{sup 2}=0, {Delta}s, is found to be {Delta}s=0.08{+-}0.26.

The MiniBooNE experiment at Fermilab reports results from a search for {nu}{sub {mu}{yields}{nu}e} oscillations, using a data sample corresponding to 5.66x10{sup 20} protons on target. An excess of 20.9{+-}14.0 events is observed in the energy range 475

MiniBooNE reports the first absolute cross sections for neutral current single {pi}{sup 0} production on CH{sub 2} induced by neutrino and antineutrino interactions measured from the largest sets of NC {pi}{sup 0} events collected to date. The principal result consists of differential cross sections measured as functions of {pi}{sup 0} momentum and {pi}{sup 0} angle averaged over the neutrino flux at MiniBooNE. We find total cross sections of (4.76 {+-} 0.05{sub stat} {+-} 0.40{sub sys}) x 10{sup -40} cm{sup 2}/nucleon at a mean energy of = 808 MeV and (1.48 {+-} 0.05{sub stat} {+-} 0.14{sub sys}) x 10{sup -40} cm{sup 2}/nucleon at a mean energy of = 664 MeV for {nu}{sub {mu}} and {bar {nu}}{sub {mu}} induced production, respectively. In addition, we have included measurements of the neutrino and antineutrino total cross sections for incoherent exclusive NC 1{pi}{sup 0} production corrected for the effects of final state interactions to compare to prior results.

We present a search for core-collapse supernovae in the Milky Way galaxy, using the MiniBooNE neutrino detector. No evidence is found for core-collapse supernovae occurring in our Galaxy in the period from December 14, 2004 to July 31, 2008, corresponding to 98% live time for collection. We set a limit on the core-collapse supernova rate out to a distance of 13.4 kpc to be less than 0.69 supernovae per year at 90% C. L., We acknowledge the support of Fermilab, the Department of Energy, and the National Science Foundation. We are grateful to John Beacom for his valuable insight and advice. We thank Alessandro Mirizzi, Georg G. Raffelt, and Pasquale D. Serpico for providing the probability distribution for the Milky Way.

There is accumulating evidence for a difference between neutrino and antineutrino oscillations at the {approx}1 eV{sup 2} scale. The MiniBooNE experiment observes an unexplained excess of electron-like events at low energies in neutrino mode, which may be due, for example, to either a neutral current radiative interaction, sterile neutrino decay, or to neutrino oscillations involving sterile neutrinos and which may be related to the LSND signal. No excess of electron-like events (-0.5 {+-} 7.8 {+-} 8.7), however, is observed so far at low energies in antineutrino mode. Furthermore, global 3+1 and 3+2 sterile neutrino fits to the world neutrino and antineutrino data suggest a difference between neutrinos and antineutrinos with significant (sin{sup 2} 2{theta}{sub {mu}{mu}} {approx} 35%) {bar {nu}}{sub {mu}} disappearance. In order to test whether the low-energy excess is due to neutrino oscillations and whether there is a difference between {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance, we propose building a second MiniBooNE detector at (or moving the existing MiniBooNE detector to) a distance of {approx}200 m from the Booster Neutrino Beam (BNB) production target. With identical detectors at different distances, most of the systematic errors will cancel when taking a ratio of events in the two detectors, asmore » the neutrino flux varies as 1/r{sup 2} to a calculable approximation. This will allow sensitive tests of oscillations for both {nu}{sub e} and {bar {nu}} appearance and {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance. Furthermore, a comparison between oscillations in neutrino mode and antineutrino mode will allow a sensitive search for CP and CPT violation in the lepton sector at short baseline ({Delta}m{sup 2} > 0.1 eV{sup 2}). Finally, by comparing the rates for a neutral current (NC) reaction, such as NC {pi}{sup 0} scattering or NC elastic scattering, a direct search for sterile neutrinos will be made. The initial amount of running time requested for the near detector will be a total of {approx}2E20 POT divided between neutrino mode and antineutrino mode, which will provide statistics comparable to what has already been collected in the far detector. A thorough understanding of this short-baseline physics will be of great importance to future long-baseline oscillation experiments.« less

The MiniBooNE Collaboration reports initial results from a search for nu{sub m}u->nu{sub e} oscillations. A signal-blind analysis was performed using a data sample corresponding to 3.39x10{sup 20} protons on target. The data are consistent with background prediction across the full range of neutrino energy reconstructed assuming quasielastic scattering, 200

The MiniBooNE Collaboration reports a search for nu(mu) and nu(mu) disappearance in the Delta m(2) region of 0.5-40 eV(2). These measurements are important for constraining models with extra types of neutrinos, extra dimensions, and CPT violation. Fits to the shape of the nu(mu) and nu(mu) energy spectra reveal no evidence for disappearance at the 90% confidence level (C.L.) in either mode. The test of nu(mu) disappearance probes a region below Delta m(2)=40 eV(2) never explored before., We acknowledge the support of Fermilab, the Department of Energy, and the National Science Foundation. We thank Los Alamos National Laboratory for LDRD funding. We also acknowledge the use of Condor software in the analysis the data.

Using a high-statistics sample of anti-neutrino charged current quasi-elastic (CCQE) events, MiniBooNE reports the challenges in measuring parameters within the Relativistic Fermi Gas model. As the CCQE analysis has been completed in MiniBooNE's neutrino data, particular attention is paid to the differences in CCQE interactions between the two running modes., Comment: NuInt '09 conference proceedings. Four pages, five figures

The neutrino-induced charged-current quasi-elastic (CCQE, $\nu_l+n\to l^-+p$ or $\bar\nu_l+p\to l^++n$) interaction is the most abundant interaction around 1 GeV, and it is the most fundamental channel to study neutrino oscillations. Recently, MiniBooNE published both muon neutrino and muon anti-neutrino double differential cross sections on carbon. In this review, we describe the details of these analyses and include some historical remarks., Comment: Preprint of an article submitted for consideration in Modern Physics Letter A \c{opyright} 2014 [copyright World Scientific Publishing Company] http://www.worldscinet.com/mpla

A measurement of the neutrino flux component of the anti-neutrino mode beam observed by the MiniBooNE detector is presented. We find the predicted νμ flux in the anti-neutrino beam should be scaled by 0.65±0.23 (statistical and systematic error included) over all reconstructed energies.

The sidereal time dependence of MiniBooNE ν[subscript e] and ν[over-bar][subscript e] appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov–Smirnov (K–S) test shows both the ν[subscript e] and ν[over-bar][subscript e] appearance data are compatible with the null sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the ν[subscript e] appearance data prefer a sidereal time-independent solution, and the ν[over-bar][subscript e] appearance data slightly prefer a sidereal time-dependent solution. Limits of order 10−20 GeV10−20 GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for ν[subscript μ] →ν[subscript e] and ν[over-bar][subscript μ]→ν[over-bar][subscript e] oscillations. The fit values and limits of combinations of SME coefficients are provided., Fermi National Accelerator Laboratory, United States. Dept. of Energy, National Science Foundation (U.S.), Indiana University, Bloomington. Center for Spacetime Symmetries