We present an analysis of MicroBooNE data with a signature of one muon, no pions, and at least one proton above a momentum threshold of 300 MeV/c(CC0πNp). This is the first differential cross-section ...measurement of this topology in neutrino-argon interactions. We achieve a significantly lower proton momentum threshold than previous carbon and scintillator-based experiments. Using data collected from a total of approximately 1.6 × 1020 protons on target, we measure the muon neutrino cross section for the CC0πNp interaction channel in argon at MicroBooNE in the Booster Neutrino Beam which has a mean energy of around 800 MeV. We present the results from a data sample with estimated efficiency of 29% and purity of 76% as differential cross sections in five reconstructed variables: the muon momentum and polar angle, the leading proton momentum and polar angle, and the muon-proton opening angle. We include smearing matrices that can be used to "forward fold" theoretical predictions for comparison with these data. We compare the measured differential cross sections to a number of recent theory predictions demonstrating largely good agreement with this first-ever dataset on argon.
We present the performance of a semantic segmentation network, sparsessnet, that provides pixel-level classification of MicroBooNE data. The MicroBooNE experiment employs a liquid argon time ...projection chamber for the study of neutrino properties and interactions. sparsessnet is a submanifold sparse convolutional neural network, which provides the initial machine learning based algorithm utilized in one of MicroBooNEs νe-appearance oscillation analyses. The network is trained to categorize pixels into five classes, which are reclassified into two classes more relevant to the current analysis. The output of sparsessnet is a key input in further analysis steps. This technique, used for the first time in liquid argon time projection chambers data and is an improvement compared to a previously used convolutional neural network, both in accuracy and computing resource utilization. The accuracy achieved on the test sample is ≥ 99 %. For full neutrino interaction simulations, the time for processing one image is ≈ 0.5 sec , the memory usage is at 1 GB level, which allows utilization of most typical CPU worker machine.
Primary challenges for current and future precision neutrino experiments using liquid argon time projection chambers (LArTPCs) include understanding detector effects and quantifying the associated ...systematic uncertainties. This paper presents a novel technique for assessing and propagating LArTPC detector-related systematic uncertainties. The technique makes modifications to simulation waveforms based on a parameterization of observed differences in ionization signals from the TPC between data and simulation, while remaining insensitive to the details of the detector model. The modifications are then used to quantify the systematic differences in low- and high-level reconstructed quantities. This approach could be applied to future LArTPC detectors, such as those used in SBN and DUNE.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A
bstract
The MicroBooNE liquid argon time projection chamber located at Fermilab is a neutrino experiment dedicated to the study of short-baseline oscillations, the measurements of neutrino cross ...sections in liquid argon, and to the research and development of this novel detector technology. Accurate and precise measurements of calorimetry are essential to the event reconstruction and are achieved by leveraging the TPC to measure deposited energy per unit length along the particle trajectory, with mm resolution. We describe the non-uniform calorimetric reconstruction performance in the detector, showing dependence on the angle of the particle trajectory. Such non-uniform reconstruction directly affects the performance of the particle identification algorithms which infer particle type from calorimetric measurements. This work presents a new particle identification method which accounts for and effectively addresses such non-uniformity. The newly developed method shows improved performance compared to previous algorithms, illustrated by a 93.7% proton selection efficiency and a 10% muon mis-identification rate, with a fairly loose selection of tracks performed on beam data. The performance is further demonstrated by identifying exclusive final states in
ν
μ
CC
interactions. While developed using MicroBooNE data and simulation, this method is easily applicable to future LArTPC experiments, such as SBND, ICARUS, and DUNE.
The T2K experiment presents new measurements of neutrino oscillation parameters using
19.7
(
16.3
)
×
10
20
protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the ...previous analysis, an additional
4.7
×
10
20
POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on
sin
2
θ
13
and the impact of priors on the
δ
CP
measurement. Both analyses prefer the normal mass ordering and upper octant of
sin
2
θ
23
with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on
sin
2
θ
13
from reactors,
sin
2
θ
23
=
0
.
561
-
0.032
+
0.021
using Feldman–Cousins corrected intervals, and
Δ
m
32
2
=
2
.
494
-
0.058
+
0.041
×
10
-
3
eV
2
using constant
Δ
χ
2
intervals. The CP-violating phase is constrained to
δ
CP
=
-
1
.
97
-
0.70
+
0.97
using Feldman–Cousins corrected intervals, and
δ
CP
=
0
,
π
is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than
2
σ
credible level using a flat prior in
δ
CP
,
and just below
2
σ
using a flat prior in
sin
δ
CP
.
When the external constraint on
sin
2
θ
13
is removed,
sin
2
θ
13
=
28
.
0
-
6.5
+
2.8
×
10
-
3
,
in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.
Abstract
An accurate and efficient event reconstruction is required
to realize the full scientific capability of liquid argon time
projection chambers (LArTPCs). The current and future neutrino
...experiments that rely on massive LArTPCs create a need for new ideas
and reconstruction approaches. Wire-Cell, proposed in recent years,
is a novel tomographic event reconstruction method for LArTPCs. The
Wire-Cell 3D imaging approach capitalizes on charge, sparsity, time,
and geometry information to reconstruct a topology-agnostic 3D image
of the ionization electrons prior to pattern recognition. A second
novel method, the many-to-many charge-light matching, then pairs the
TPC charge activity to the detected scintillation light signal, thus
enabling a powerful rejection of cosmic-ray muons in the MicroBooNE
detector. A robust processing of the scintillation light signal and
an appropriate clustering of the reconstructed 3D image are
fundamental to this technique. In this paper, we describe the
principles and algorithms of these techniques and their successful
application in the MicroBooNE experiment. A quantitative evaluation
of the performance of these techniques is presented. Using these
techniques, a 95% efficient pre-selection of neutrino
charged-current events is achieved with a 30-fold reduction of
non-beam-coincident cosmic-ray muons, and about 80% of the selected
neutrino charged-current events are reconstructed with at least 70%
completeness and 80% purity.
We present the performance of a semantic segmentation network, SparseSSNet, that provides pixel-level classification of MicroBooNE data. The MicroBooNE experiment employs a liquid argon time ...projection chamber for the study of neutrino properties and interactions. SparseSSNet is a submanifold sparse convolutional neural network, which provides the initial machine learning based algorithm utilized in one of MicroBooNE's ν_e-appearance oscillation analyses. The network is trained to categorize pixels into five classes, which are re-classified into two classes more relevant to the current analysis. The output of SparseSSNet is a key input in further analysis steps. This technique, used for the first time in liquid argon time projection chambers data and is an improvement compared to a previously used convolutional neural network, both in accuracy and computing resource utilization. The accuracy achieved on the test sample is ≥99%. For full neutrino interaction simulations, the time for processing one image is ≈ 0.5 sec, the memory usage is at 1 GB level, which allows utilization of most typical CPU worker machine.
Abstract
Wire-Cell is a 3D event reconstruction package for liquid
argon time projection chambers. Through geometry, time, and drifted
charge from multiple readout wire planes, 3D space points with
...associated charge are reconstructed prior to the pattern recognition
stage. Pattern recognition techniques, including track trajectory
and d
Q
/d
x
(ionization charge per unit length) fitting, 3D neutrino
vertex fitting, track and shower separation, particle-level
clustering, and particle identification are then applied on these 3D
space points as well as the original 2D projection measurements. A
deep neural network is developed to enhance the reconstruction of
the neutrino interaction vertex. Compared to traditional
algorithms, the deep neural network boosts the vertex efficiency by
a relative 30% for charged-current ν
e
interactions. This
pattern recognition achieves 80–90% reconstruction efficiencies
for primary leptons, after a 65.8% (72.9%) vertex efficiency for
charged-current ν
e
(ν
μ
) interactions. Based on the
resulting reconstructed particles and their kinematics, we also
achieve 15-20% energy reconstruction resolutions for
charged-current neutrino interactions.
Abstract
Accurate knowledge of electron transport properties is vital to understanding the information provided by liquid argon time projection chambers (LArTPCs). Ionization electron drift-lifetime, ...local electric field distortions caused by positive ion accumulation, and electron diffusion can all significantly impact the measured signal waveforms. This paper presents a measurement of the effective longitudinal electron diffusion coefficient, D
L
, in MicroBooNE at the nominal electric field strength of 273.9 V/cm. Historically, this measurement has been made in LArTPC prototype detectors. This represents the first measurement in a large-scale (85 tonne active volume) LArTPC operating in a neutrino beam. This is the largest dataset ever used for this measurement. Using a sample of ∼70,000 through-going cosmic ray muon tracks tagged with MicroBooNE's cosmic ray tagger system, we measure D
L
= 3.74
+0.28
-0.29
cm
2
/s.
Abstract
is a near-surface liquid argon (LAr) time projection
chamber (TPC) located at Fermilab. We measure muons originating from
cosmic interactions in the atmosphere using both the charge
...collection and light readout detectors. The data is compared with
the cosmic-ray simulation. Agreement is found between the
observation, simulation and previous results. Furthermore, the
angular resolution of the reconstructed muons inside the TPC is
studied in simulation.
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