Booster Neutrino Experiment Research Articles

Liquid Argon Time Projection Chamber Trigger Development with MicroBooNE

The Micro Booster Neutrino Experiment (MicroBooNE) is a Liquid Argon Time Projection Chamber (LArTPC) neutrino detector at Fermilab that has been operating since 2015. It aims to perform v-Ar cross-section measurements, explore the low-energy excess reported by the MiniBooNE experiment and perform a combined search for sterile neutrino oscillations as part of three LArTPCs that make up the Short Baseline Neutrino (SBN) Program at Fermilab. Since MicroBooNE is currently in an R&D phase, it offers a unique opportunity for the implementation and testing of TPC-based triggers as R&D towards the Deep Underground Neutrino Experiment (DUNE). One of the technical challenges of DUNE that we aim to address with this study is that of efficient self-triggering of a LArTPC utilizing TPC signal information. This capability will enable searches for rare processes in DUNE, such as neutrino interactions from a potential galactic supernova burst. This talk will describe the MicroBooNE TPC readout system and ongoing R&D efforts to develop and demonstrate TPC-based triggering.

Sterile Neutrinos with Neutrino Telescopes

Searches for light sterile neutrinos are motivated by the unexpected observation of an electron neutrino appearance in short-baseline experiments, such as the Liquid Scintillator Neutrino Detector (LSND) and the Mini Booster Neutrino Experiment (MiniBooNE). In light of these unexpected results, a campaign using natural and anthropogenic sources to find the light (mass-squared-difference around 1 eV2) sterile neutrinos is underway. Among the natural sources, atmospheric neutrinos provide a unique gateway to search for sterile neutrinos due to the broad range of baseline-to-energy ratios, L/E, and the presence of significant matter effects. Since the atmospheric neutrino flux rapidly falls with energy, studying its highest energy component requires gigaton-scale neutrino detectors. These detectors—often known as neutrino telescopes since they are designed to observe tiny astrophysical neutrino fluxes—have been used to perform searches for light sterile neutrinos, and researchers have found no significant signal to date. This brief review summarizes the current status of searches for light sterile neutrinos with neutrino telescopes deployed in solid and liquid water.

Liquid argon photodetection systems for neutrino detectors: A minireview

A growing number of experiments with particle detectors using liquid argon are currently being carried out, as this is an excellent means of detecting neutrinos. These experiments develop different capture and measurement systems of the photons generated by the excitation of the argon atoms when a charged particle passes. New low-cost technologies, more sensitive and efficient detection methods, hardware and electronics, optimize and take advantage of the characteristics of the processes involved. This minireview presents the main characteristics of photodetection systems used in some of the most important experiments for the finding of neutrinos, particularly those that use liquid argon at cryogenic temperatures (-186 °C), such as Deep Underground Neutrino Experiment and the Micro Booster Neutrino Experiment. In addition, this article presents a comparison of the advances of each cryogenic photodetection system with the aim of promoting the use of this technology in new research fields.

Light sterile neutrinos and their implications on currently running long-baseline and neutrinoless double-beta decay experiments

Recent νe appearance data from the Mini Booster Neutrino Experiment support the excess of events reported by the Liquid Scintillator Neutrino Detector, which provides an indirect hint of the existence of eV-scale sterile neutrinos. As these sterile neutrinos can mix with the standard active neutrinos, in this paper we explore the effect of such active–sterile mixing on the determination of various oscillation parameters by the currently running long-baseline neutrino experiments T2K and NOνA. We find that the existence of sterile neutrinos can lead to new kinds of degeneracies among these parameters which would substantially deteriorate the mass hierarchy sensitivity of the NOνA experiment. We further notice that the inclusion of data from the T2K experiment helps in resolving the degeneracies. The impact of new CP-violating phases δ14 and δ34 on the maximal CP violation exclusion sensitivity for the NOνA experiment has also been illustrated. Finally, we discuss the implication of such light sterile neutrinos on neutrinoless double-beta decay processes in line with recent experimental results, as well as on the sensitivity reach of future experiments.

Erratum: Many-body interactions of neutrinos with nuclei: Observables [Phys. Rev. C86, 014614 (2012)

Background: The total inclusive cross sections obtained for quasielastic (QE) scattering in the Mini Booster Neutrino Experiment (MiniBooNE) are significantly larger than those calculated by all models based on the impulse approximation and using the world average value for the axial mass of $M_A \approx 1 \GeV$. This discrepancy has led to various, quite different explanations in terms of increased axial masses, changes in the functional form of the axial form factor, increased vector strength in nuclei, and initial two-particle interactions. This is disconcerting since the neutrino energy reconstruction depends on the reaction mechanism. Purpose: We investigate whether exclusive observables, such as nucleon knock-out, can be used to distinguish between the various proposed reaction mechanisms. We determine the influence of 2p-2h excitations on the energy reconstruction. Method: We use the Giessen Boltzmann--Uehling--Uhlenbeck (GiBUU) model to predict numbers and spectra of knock-out nucleons. The model is extended by incorporating a simple, but realistic treatment of initial 2p-2h excitations. Results: We show numbers and spectra of knock-out nucleons and show their sensitivity to the presence of 2p-2h initial excitations. We also discuss the influence of 2p-2h excitations on the neutrino energy reconstruction. Conclusions: 2p-2h excitations do lead to an increase in the number $n$ of knock-out nucleons for $n \ge 2$ while only the $n=1$ knock-out remains a clean signal of true QE scattering. The spectra of knock-out nucleons do also change, but their qualitative shape remains as before. In the energy reconstruction 2p-2h interactions lead to a downward shift of the reconstructed energy; this effect of 2p-2h excitations disappears at higher energies because the 2p-2h influence is spread out over a wider energy range.

Many-body interactions of neutrinos with nuclei: Observables

Background: The total inclusive cross sections obtained for quasielastic (QE) scattering in the Mini Booster Neutrino Experiment (MiniBooNE) are significantly larger than those calculated by all models based on the impulse approximation and using the world average value for the axial mass of ${M}_{A}\ensuremath{\approx}1\phantom{\rule{0.28em}{0ex}}\mathrm{GeV}$. This discrepancy has led to various, quite different explanations in terms of increased axial masses, changes in the functional form of the axial form factor, increased vector strength in nuclei, and initial two-particle interactions. This is disconcerting since the neutrino energy reconstruction depends on the reaction mechanism.Purpose: We investigate whether exclusive observables, such as nucleon knockout, can be used to distinguish between the various proposed reaction mechanisms. We determine the influence of 2p-2h excitations on the neutrino energy reconstruction.Method: We extend the Giessen Boltzmann--Uehling--Uhlenbeck (GiBUU) model by explicitly incorporating initial 2p-2h excitations.Results: We calculate inclusive cross sections and numbers and spectra of knockout nucleons and show their sensitivity to the presence of 2p-2h initial excitations. We also discuss the influence of 2p-2h excitations on the neutrino energy reconstruction.Conclusions: Inclusive double-differential cross sections, depending only on muon variables, are fairly insensitive to the reaction mechanism. 2p-2h excitations lead to an increase in the number $n$ of knockout nucleons for $n\ensuremath{\geqslant}2$, while only the $n=1$ knockout remains a clean signal of true QE scattering. The spectra of knockout nucleons are also changed, but their shape is hardly affected. In the energy reconstruction, 2p-2h interactions as well as $\ensuremath{\Delta}$ excitations lead to a downward shift of the reconstructed energy; this effect of 2p-2h excitations disappears at higher energies because the 2p-2h influence is spread out over a wider energy range.

The extended-track event reconstruction for MiniBooNE

The Booster Neutrino Experiment (MiniBooNE) searches for ν μ → ν e oscillations using the ~ 1 GeV neutrino beam produced by the FNAL Booster synchrotron. The array of photomultiplier tubes (PMTs) lining the MiniBooNE detector records Cherenkov and scintillation photons from the charged particles produced in neutrino interactions. We describe a maximum likelihood fitting algorithm used to reconstruct the basic properties (position, direction, energy) of these particles from the charges and times measured by the PMTs. The likelihoods returned from fitting an event to different particle hypotheses are used to categorize it as a signal ν e event or as one of the background ν μ processes, in particular charged current quasi-elastic scattering and neutral current π 0 production. The reconstruction and event selection techniques described here can be applied to current and future neutrino experiments using similar Cherenkov-based detection.

Neutrino flux prediction at MiniBooNE

The Booster Neutrino Experiment (MiniBooNE) searches for numu-to-nue oscillations using the O(1 GeV) neutrino beam produced by the Booster synchrotron at the Fermi National Accelerator Laboratory (FNAL). The Booster delivers protons with 8 GeV kinetic energy (8.89 GeV/c momentum) to a beryllium target, producing neutrinos from the decay of secondary particles in the beam line. We describe the Monte Carlo simulation methods used to estimate the flux of neutrinos from the beamline incident on the MiniBooNE detector for both polarities of the focussing horn. The simulation uses the Geant4 framework for propagating particles, accounting for electromagnetic processes and hadronic interactions in the beamline materials, as well as the decay of particles. The absolute double differential cross sections of pion and kaon production in the simulation have been tuned to match external measurements, as have the hadronic cross sections for nucleons and pions. The statistical precision of the flux predictions is enhanced through reweighting and resampling techniques. Systematic errors in the flux estimation have been determined by varying parameters within their uncertainties, accounting for correlations where appropriate.

Nu physics with SciBooNE

SciBooNE, the SciBar Booster Neutrino Experiment, has been collecting data at Fermilab for the past year. With a fine grained tracking vertex detector, SciBooNE will measure neutrino and antineutrino cross sections on carbon near 1 GeV with unprecedented precision. These cross sections will be used as external constraints for the T2K neutrino oscillation experiment. SciBooNE also serves as a near detector for MiniBooNE. Experimental progress and preliminary results will be presented.

Anomaly Mediated Neutrino-Photon Interactions at Finite Baryon Density

We propose new physical processes based on the axial vector anomaly and described by the Wess-Zumino-Witten term that couples the photon, Z-boson, and the omega-meson. The interaction takes the form of a pseudo-Chern-Simons term, approximately E(munurhosigma)omega(mu)ZnuFrhosigma. This term induces neutrino-photon interactions at finite baryon density via the coupling of the Z-boson to neutrinos. These interactions may be detectable in various laboratory and astrophysical arenas. The new interactions may account for the excess observed at the Fermilab Booster Neutrino Experiment MiniBooNE. They also produce a competitive contribution to neutron star cooling at temperatures greater, similar10(9) K. These processes and related axion-photon interactions at finite baryon density appear to be relevant in many astrophysical regimes.

Neutrino Oscillation Search at MiniBooNE

This article reports the status of a ν μ → ν e oscillation search in MiniBooNE (Booster Neutrino Experiment) experiment. If an appearance signal is observed, it will imply Physics Beyond the Standard Model such as the existence of light sterile neutrino.

MiniBooNE

The physics motivations, design, and status of the Booster Neutrino Experiment at Fermilab, MiniBooNE, are briefly discussed. Particular emphasis is given on the ongoing preparatory work that is needed for the MiniBooNE muon neutrino to electron neutrino oscillation appearance search. This search aims to confirm or refute in a definitive and independent way the evidence for neutrino oscillations reported by the LSND experiment.

Update on MiniBooNE

MiniBooNE (Booster Neutrino Experiment) is searching for ν μ → ν e oscillations in the neutrino beam produced by the 8 GeV Booster synchrotron at Fermilab. The Booster has delivered 3.66 × 10 20 protons-on-target with over 380 thousand neutrino events recorded in the detector since September 2002. MiniBooNE is now accumulating enough data to achieve its goal of conclusively confirming or refuting the evidence for neutrino oscillations observed by the LSND experiment.

Neutrino cross section measurements at MiniBooNE

MiniBooNE (Booster Neutrino Experiment) is accumulating a large sample of O ( 1 GeV ) ν μ interactions in the neutrino beam produced by the 8 GeV Booster synchrotron at Fermilab. Analyses of ν μ charged current quasielastic scattering and neutral current π 0 production, as well as neutral current elastic scattering and charged current π + production are in progress.

Neutral Current π0 Interactions at MiniBooNE

MiniBooNE, the Mini Booster Neutrino Experiment at Fermilab, will search for the appearance of electron neutrinos in a beam of muon neutrinos, and in the process will accumulate more neutrino interactions in the 0 − 2 GeV energy range than all past experiments. This work presents preliminary results from the neutral current π0 analysis at MiniBooNE, with comparisons of the NUANCE, NEUGEN, and NEUT neutrino cross section Monte Carlos. Also presented are comparisons of three Monte Carlo simulations with MiniBooNE data taken during the running period from September, 2002, to September, 2003.