82 research outputs found
Improved Limits on Millicharged Particles Using the ArgoNeuT Experiment at Fermilab
A search for millicharged particles, a simple extension of the standard
model, has been performed with the ArgoNeuT detector exposed to the Neutrinos
at the Main Injector beam at Fermilab. The ArgoNeuT Liquid Argon Time
Projection Chamber detector enables a search for millicharged particles through
the detection of visible electron recoils. We search for an event signature
with two soft hits (MeV-scale energy depositions) aligned with the upstream
target. For an exposure of the detector of protons on
target, one candidate event has been observed, compatible with the expected
background. This search is sensitive to millicharged particles with charges
between and and with masses in the range from GeV
to GeV. This measurement provides leading constraints on millicharged
particles in this large unexplored parameter space region.Comment: Version accepted by PR
First Measurement of Electron Neutrino Scattering Cross Section on Argon
We report the first electron neutrino cross section measurements on argon,
based on data collected by the ArgoNeuT experiment running in the GeV-scale
NuMI beamline at Fermilab. A flux-averaged total and
a lepton angle differential cross section are extracted using 13 and
events identified with fully-automated selection and
reconstruction. We employ electromagnetic-induced shower characterization and
analysis tools developed to identify -like events among
complex interaction topologies present in ArgoNeuT data ( GeV and GeV).
The techniques are widely applicable to searches for electron-flavor appearance
at short- and long-baseline using liquid argon time projection chamber
technology. Notably, the data-driven studies of GeV-scale
interactions presented in this Letter probe an energy
regime relevant for future DUNE oscillation physics.Comment: added acknowledgement
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Calibration of the charge and energy loss per unit length of the MicroBooNE liquid argon time projection chamber using muons and protons
We describe a method used to calibrate the position- and time-dependent response of the MicroBooNE liquid argon time projection chamber anode wires to ionization particle energy loss. The method makes use of crossing cosmic-ray muons to partially correct anode wire signals for multiple effects as a function of time and position, including cross-connected TPC wires, space charge effects, electron attachment to impurities, diffusion, and recombination. The overall energy scale is then determined using fully-contained beam-induced muons originating and stopping in the active region of the detector. Using this method, we obtain an absolute energy scale uncertainty of 2% in data. We use stopping protons to further refine the relation between the measured charge and the energy loss for highly-ionizing particles. This data-driven detector calibration improves both the measurement of total deposited energy and particle identification based on energy loss per unit length as a function of residual range. As an example, the proton selection efficiency is increased by 2% after detector calibration
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Reconstruction and measurement of (100) MeV energy electromagnetic activity from π0 arrow γγ decays in the MicroBooNE LArTPC
We present results on the reconstruction of electromagnetic (EM) activity from photons produced in charged current νμ interactions with final state π0s. We employ a fully-automated reconstruction chain capable of identifying EM showers of (100) MeV energy, relying on a combination of traditional reconstruction techniques together with novel machine-learning approaches. These studies demonstrate good energy resolution, and good agreement between data and simulation, relying on the reconstructed invariant π0 mass and other photon distributions for validation. The reconstruction techniques developed are applied to a selection of νμ + Ar → μ + π0 + X candidate events to demonstrate the potential for calorimetric separation of photons from electrons and reconstruction of π0 kinematics
Design and construction of the MicroBooNE Cosmic Ray Tagger system
The MicroBooNE detector utilizes a liquid argon time projection chamber
(LArTPC) with an 85 t active mass to study neutrino interactions along the
Booster Neutrino Beam (BNB) at Fermilab. With a deployment location near ground
level, the detector records many cosmic muon tracks in each beam-related
detector trigger that can be misidentified as signals of interest. To reduce
these cosmogenic backgrounds, we have designed and constructed a TPC-external
Cosmic Ray Tagger (CRT). This sub-system was developed by the Laboratory for
High Energy Physics (LHEP), Albert Einstein center for fundamental physics,
University of Bern. The system utilizes plastic scintillation modules to
provide precise time and position information for TPC-traversing particles.
Successful matching of TPC tracks and CRT data will allow us to reduce
cosmogenic background and better characterize the light collection system and
LArTPC data using cosmic muons. In this paper we describe the design and
installation of the MicroBooNE CRT system and provide an overview of a series
of tests done to verify the proper operation of the system and its components
during installation, commissioning, and physics data-taking
First measurement of the cross section for and induced single charged pion production on argon using ArgoNeuT
We report on the first cross section measurement of charged-current single
charged pion production by neutrinos and antineutrinos on argon. This analysis
was performed using the ArgoNeuT detector exposed to the NuMI beam at Fermilab.
The measurements are presented as functions of muon momentum, muon angle, pion
angle, and angle between muon and pion. The flux-averaged cross sections are
measured to be for neutrinos at a mean energy of 9.6 GeV and
for antineutrinos at a mean energy of 3.6 GeV with
the charged pion momentum above 100 MeV/. The results are compared with
several model predictions
Multidifferential cross section measurements of νμ -argon quasielasticlike reactions with the MicroBooNE detector
We report on a flux-integrated multidifferential measurement of charged-current muon neutrino scattering on argon with one muon and one proton in the final state using the Booster Neutrino Beam and MicroBooNE detector at Fermi National Accelerator Laboratory. The data are studied as a function of various kinematic imbalance variables and of a neutrino energy estimator, and are compared to a number of event generator predictions. We find that the measured cross sections in different phase-space regions are sensitive to nuclear effects. Our results provide precision data to test and improve the neutrino-nucleus interaction models needed to perform high-accuracy oscillation analyses. Specific regions of phase space are identified where further model refinements are most needed
First Double-Differential Measurement of Kinematic Imbalance in Neutrino Interactions with the MicroBooNE Detector
We report the first measurement of flux-integrated double-differential quasielasticlike neutrino-argon cross sections, which have been made using the Booster Neutrino Beam and the MicroBooNE detector at Fermi National Accelerator Laboratory. The data are presented as a function of kinematic imbalance variables which are sensitive to nuclear ground-state distributions and hadronic reinteraction processes. We find that the measured cross sections in different phase-space regions are sensitive to different nuclear effects. Therefore, they enable the impact of specific nuclear effects on the neutrino-nucleus interaction to be isolated more completely than was possible using previous single-differential cross section measurements. Our results provide precision data to help test and improve neutrino-nucleus interaction models. They further support ongoing neutrino-oscillation studies by establishing phase-space regions where precise reaction modeling has already been achieved
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