The Short-Baseline Near Detector time projection chamber is unique in the design of its charge readout planes. These anode plane assemblies (APAs) have been fabricated and assembled to meet strict ...accuracy and precision requirements: wire spacing of 3 mm ± 0.5 mm and wire tension of 7 N ± 1 N across 3,964 wires per APA, and flatness within 0.5 mm over the 4 m × 2.5 m extent of each APA . This paper describes the design, manufacture and assembly of these key detector components, with a focus on the quality assurance at each stage.
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. Here, 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.
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.
We report the first double-differential cross section measurement of
neutral-current neutral pion (NC$\pi^0$) production in neutrino-argon
scattering, as well as single-differential measurements of ...the same channel in
terms of final states with and without protons. The kinematic variables of
interest for these measurements are the $\pi^0$ momentum and the $\pi^0$
scattering angle with respect to the neutrino beam. A total of 4971 candidate
NC$\pi^0$ events fully-contained within the MicroBooNE detector are selected
using data collected at a mean neutrino energy of $\sim 0.8$ GeV from
$6.4\times10^{20}$ protons on target from the Booster Neutrino Beam at the
Fermi National Accelerator Laboratory. After extensive data-driven model
validation to ensure unbiased unfolding, the Wiener-SVD method is used to
extract nominal flux-averaged cross sections. The results are compared to
predictions from commonly used neutrino event generators, which tend to
overpredict the measured NC$\pi^0$ cross section, especially in the 0.2-0.5
GeV/c $\pi^0$ momentum range, at forward scattering angles, and when at least
one proton is present in the final state. These measurements show sensitivity
to a variety of features that complicate the description of NC$\pi^0$
production including the form factors describing the elementary neutrino
interaction and the final state interactions of the outgoing particles in the
residual argon nucleus. This data will help improve the modeling of NC$\pi^0$
production, which represents a major background in measurements of
charge-parity violation in the neutrino sector and in searches for new physics
beyond the Standard Model.
Phys. Rev. D 110, 013006 (2024) A detailed understanding of inclusive muon neutrino charged-current
interactions on argon is crucial to the study of neutrino oscillations in
current and future ...experiments using liquid argon time projection chambers. To
that end, we report a comprehensive set of differential cross section
measurements for this channel that simultaneously probe the leptonic and
hadronic systems by dividing the channel into final states with and without
protons. Measurements of the proton kinematics and proton multiplicity of the
final state are also presented. For these measurements, we utilize data
collected with the MicroBooNE detector from 6.4$\times10^{20}$ protons on
target from the Fermilab Booster Neutrino Beam at a mean neutrino energy of
approximately 0.8 GeV. We present in detail the cross section extraction
procedure, including the unfolding, and model validation that uses data to
model comparisons and the conditional constraint formalism to detect
mismodeling that may introduce biases to extracted cross sections that are
larger than their uncertainties. The validation exposes insufficiencies in the
overall model, motivating the inclusion of an additional data-driven
reweighting systematic to ensure the accuracy of the unfolding. The extracted
results are compared to a number of event generators and their performance is
discussed with a focus on the regions of phase-space that indicate the greatest
need for modeling improvements.
Phys. Rev. Lett. 132, 151801 Published 10 April 2024 We present a measurement of $\eta$ production from neutrino interactions on
argon with the MicroBooNE detector. The modeling of resonant neutrino
...interactions on argon is a critical aspect of the neutrino oscillation physics
program being carried out by the DUNE and Short Baseline Neutrino programs.
$\eta$ production in neutrino interactions provides a powerful new probe of
resonant interactions, complementary to pion channels, and is particularly
suited to the study of higher-order resonances beyond the $\Delta(1232)$. We
measure a flux-integrated cross section for neutrino-induced $\eta$ production
on argon of $3.22 \pm 0.84 \; \textrm{(stat.)} \pm 0.86 \; \textrm{(syst.)}$
$10^{-41}{\textrm{cm}}^{2}$/nucleon. By demonstrating the successful
reconstruction of the two photons resulting from $\eta$ production, this
analysis enables a novel calibration technique for electromagnetic showers in
GeV accelerator neutrino experiments.
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