The Pandora Software Development Kit and algorithm libraries perform reconstruction of neutrino interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at the Deep Underground Neutrino Experiment, which will operate four large-scale liquid argon time projection chambers at the far detector site in South Dakota, producing high-resolution images of charged particles emerging from neutrino interactions. While these high-resolution images provide excellent opportunities for physics, the complex topologies require sophisticated pattern recognition capabilities to interpret signals from the detectors as physically meaningful objects that form the inputs to physics analyses. A critical component is the identification of the neutrino interaction vertex. Subsequent reconstruction algorithms use this location to identify the individual primary particles and ensure they each result in a separate reconstructed particle. A new vertex-finding procedure described in this article integrates a U-ResNet neural network performing hit-level classification into the multi-algorithm approach used by Pandora to identify the neutrino interaction vertex. The machine learning solution is seamlessly integrated into a chain of pattern-recognition algorithms. The technique substantially outperforms the previous BDT-based solution, with a more than 20% increase in the efficiency of sub-1 cm vertex reconstruction across all neutrino flavours.

Switzerland

A. Abud

United States

R. Acciarri

Colombia

M. Acero

Brazil

M. Adames

Georgia

G. Adamov

M. Adamowski

D. Adams

United Kingdom

M. Adinolfi

C. Adriano

A. Aduszkiewicz

J. Aguilar

F. Akbar

Italy

F. Alemanno

N. Alex

K. Allison

M. Alrashed

A. Alton

Spain

R. Alvarez

T. Alves

A. Aman

H. Amar

P. Amedo

J. Anderson

C. Andreopoulos

M. Andreotti

M. Andrews

Madagascar

F. Andrianala

Portugal

S. Andringa

F. Anjarazafy

D. Antic

M. Antoniassi

M. Antonova

Mexico

A. Aranda-Fernandez

L. Arellano

E. Arrieta Diaz

M. Arroyave

J. Asaadi

Israel

A. Ashkenazi

D. Asner

L. Asquith

E. Atkin

France

D. Auguste

A. Aurisano

Ukraine

V. Aushev

D. Autiero

D. Ávila Gómez

M. Azam

F. Azfar

A. Back

H. Back

J. Back

I. Bagaturia

L. Bagby

Kazakhstan

D. Baigarashev

S. Balasubramanian

A. Balboni

P. Baldi

W. Baldini

J. Baldonedo

B. Baller

India

B. Bambah

Canada

R. Banerjee

F. Barao

Romania

D. Barbu

G. Barenboim

P. Barham Alzás

G. Barker

W. Barkhouse

G. Barr

J. Barranco Monarca

A. Barros

N. Barros

D. Barrow

J. Barrow

A. Basharina-Freshville

A. Bashyal

V. Basque

D. Basu

C. Batchelor

L. Bathe-Peters

J. Battat

F. Battisti

Türkiye

F. Bay

M. Bazetto

Peru

J. Bazo Alba

J. Beacom

E. Bechetoille

B. Behera

E. Belchior

B. Bell

G. Bell

L. Bellantoni

G. Bellettini

V. Bellini

O. Beltramello

Paraguay

C. Benitez Montiel

D. Benjamin

F. Bento Neves

J. Berger

S. Berkman

Neutrino interaction vertex reconstruction in DUNE with Pandora deep learning

<p>The determination of the direction of a stellar core collapse via its neutrino emission is crucial for the identification of the progenitor for a multimessenger follow-up. A highly effective method of reconstructing supernova directions within the Deep Underground Neutrino Experiment (DUNE) is introduced. The supernova neutrino pointing resolution is studied by simulating and reconstructing electron-neutrino charged-current absorption on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ar</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>40</mn></mrow></mmultiscripts></mrow></math> and elastic scattering of neutrinos on electrons. Procedures to reconstruct individual interactions, including a newly developed technique called “brems flipping,” as well as the burst direction from an ensemble of interactions are described. Performance of the burst direction reconstruction is evaluated for supernovae happening at a distance of 10 kpc for a specific supernova burst flux model. The pointing resolution is found to be 3.4 degrees at 68% coverage for a perfect interaction-channel classification and a fiducial mass of 40 kton, and 6.6 degrees for a 10 kton fiducial mass respectively. Assuming a 4% rate of charged-current interactions being misidentified as elastic scattering, DUNE’s burst pointing resolution is found to be 4.3 degrees (8.7 degrees) at 68% coverage.</p>

CERN

A. Abed Abud

B. Abi

M.A. Acero

M.R. Adames

B. Aimard

S. Alonso Monsalve

D.A. Andrade

M.P. Andrews

N. Anfimov

A. Ankowski

A. Antoshkin

M.A. Arroyave

J.J. Back

N. Balashov

G.J. Barker

J.L. Barrow

J.B.R. Battat

M.C.Q. Bazetto

J.L.L. Bazo Alba

J.F. Beacom

N. Benekos

J. Bernal

P. Bernardini

A. Bersani

Supernova pointing capabilities of DUNE

ProtoDUNE Single-Phase (ProtoDUNE-SP) is a 770-ton liquid argon time projection chamber that operated in a hadron test beam at the CERN Neutrino Platform in 2018. We present a measurement of the total inelastic cross section of charged kaons on argon as a function of kaon energy using 6 and <math><mrow><mn>7</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>c</mi></mrow></math> beam momentum settings. The flux-weighted average of the extracted inelastic cross section at each beam momentum setting was measured to be <math><mrow><mn>380</mn><mo>±</mo><mn>26</mn><mtext> </mtext><mtext> </mtext><mi>mbarns</mi></mrow></math> for the <math><mrow><mn>6</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>c</mi></mrow></math> setting and <math><mrow><mn>379</mn><mo>±</mo><mn>35</mn><mtext> </mtext><mtext> </mtext><mi>mbarns</mi></mrow></math> for the <math><mrow><mn>7</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>c</mi></mrow></math> setting.

M. A. Acero

M. R. Adames

M. P. Andrews

M. A. Arroyave

M. B. Azam

J. J. Back

G. J. Barker

J. L. Barrow

J. B. R. Battat

M. C. Q. Bazetto

J. L. L. Bazo Alba

J. F. Beacom

First measurement of the total inelastic cross section of positively charged kaons on argon at energies between 5.0 and 7.5 GeV

Long baseline (LBL) neutrino experiments aim to measure the neutrino oscillation parameters to high precision. These experiments use nuclear targets for neutrino scattering and hence are inflicted with complexities of nuclear effects. Nuclear effects and their percolation into sensitivity measurement of neutrino oscillations parameters are not yet fully understood and therefore need to be dealt with carefully. In a recent work [1], we reported some results on this for NOνA experiment using the kinematic method of neutrino energy reconstruction, where it was observed that the nuclear effects are important in sensitivity analysis, and inclusion of realistic detector set up specifications increases uncertainty in this analysis as compared to ideal detector case. Precise reconstruction of neutrino energy is an important component in the extraction of oscillation parameters, and it is required that the neutrino energy is reconstructed with very high precision. With this motivation, in this work, we use two methods of neutrino energy reconstruction - kinematic and calorimetric, including the nuclear effects, and study their impact on sensitivity analysis. We consider nuclear interactions such as RPA and 2p2h and compare two energy reconstruction methods with reference to events generation, measurement of neutrino oscillation parameters <math><mi>Δ</mi><msubsup><mrow><mi>m</mi></mrow><mrow><mn>32</mn></mrow><mrow><mn>2</mn></mrow></msubsup></math> and <math><msub><mrow><mi>θ</mi></mrow><mrow><mn>23</mn></mrow></msub></math> for (<math><msub><mrow><mi>ν</mi></mrow><mrow><mi>μ</mi></mrow></msub><mo>→</mo><msub><mrow><mi>ν</mi></mrow><mrow><mi>μ</mi></mrow></msub></math>) disappearance channel, mass hierarchy sensitivity, and CP-violation sensitivity for (<math><msub><mrow><mi>ν</mi></mrow><mrow><mi>μ</mi></mrow></msub><mo>→</mo><msub><mrow><mi>ν</mi></mrow><mrow><mi>e</mi></mrow></msub></math>) appearance channel of the NOνA experiment. It is observed that with an ideal detector setup, the kinematic method shows significant dependence on nuclear effects, as compared to the calorimetric method. We also investigate the impact of realistic detector setup for NOνA in these two methods (with nuclear effects) and find that the calorimetric method shows more bias (uncertainty increases) in sensitivity contours, as compared to the kinematic method. This is found to be true for both the mass hierarchies and for both neutrino and antineutrino incoming beams. The results of this study can offer useful insights into future neutrino oscillation analysis at LBL experiments (including leptonic CP phase measurement), especially when we are in the precision measurement era for the same, particularly in the context of some nuclear effects and energy reconstruction methods.

Paramita Deka

Jaydip Singh

Kalpana Bora

Impact of nuclear effects in energy reconstruction methods on sensitivity of neutrino oscillation parameters at NO A experiment

A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the <math><mi>O</mi><mo>(</mo><mn>10</mn><mo>)</mo><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math> neutrinos produced by a Galactic core-collapse supernova if one should occur during the lifetime of the experiment. The liquid-argon-based detectors planned for DUNE are expected to be uniquely sensitive to the <math><msub><mi>ν</mi><mi>e</mi></msub></math> component of the supernova flux, enabling a wide variety of physics and astrophysics measurements. A key requirement for a correct interpretation of these measurements is a good understanding of the energy-dependent total cross section <math><mi>σ</mi><mo>(</mo><msub><mi>E</mi><mi>ν</mi></msub><mo>)</mo></math> for charged-current <math><msub><mi>ν</mi><mi>e</mi></msub></math> absorption on argon. In the context of a simulated extraction of supernova <math><msub><mi>ν</mi><mi>e</mi></msub></math> spectral parameters from a toy analysis, we investigate the impact of <math><mi>σ</mi><mo>(</mo><msub><mi>E</mi><mi>ν</mi></msub><mo>)</mo></math> modeling uncertainties on DUNE’s supernova neutrino physics sensitivity for the first time. We find that the currently large theoretical uncertainties on <math><mi>σ</mi><mo>(</mo><msub><mi>E</mi><mi>ν</mi></msub><mo>)</mo></math> must be substantially reduced before the <math><msub><mi>ν</mi><mi>e</mi></msub></math> flux parameters can be extracted reliably; in the absence of external constraints, a measurement of the integrated neutrino luminosity with less than 10% bias with DUNE requires <math><mi>σ</mi><mo>(</mo><msub><mi>E</mi><mi>ν</mi></msub><mo>)</mo></math> to be known to about 5%. The neutrino spectral shape parameters can be known to better than 10% for a 20% uncertainty on the cross-section scale, although they will be sensitive to uncertainties on the shape of <math><mi>σ</mi><mo>(</mo><msub><mi>E</mi><mi>ν</mi></msub><mo>)</mo></math>. A direct measurement of low-energy <math><msub><mi>ν</mi><mi>e</mi></msub></math>-argon scattering would be invaluable for improving the theoretical precision to the needed level.

Z. Ahmad

J. Ahmed

D. A. Andrade

JINR

W. L. Anicézio Campanelli

L. O. Arnold

M. Ayala-Torres

C. Barnes

R. M. Berner

S. Bertolucci

Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment

Measurements of electrons from <math><msub><mi>ν</mi><mi>e</mi></msub></math> interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection, and solar neutrino measurements. This article describes the selection and reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector. ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and operated at CERN as a charged particle test beam experiment. A sample of low-energy electrons produced by the decay of cosmic muons is selected with a purity of 95%. This sample is used to calibrate the low-energy electron energy scale with two techniques. An electron energy calibration based on a cosmic ray muon sample uses calibration constants derived from measured and simulated cosmic ray muon events. Another calibration technique makes use of the theoretically well-understood Michel electron energy spectrum to convert reconstructed charge to electron energy. In addition, the effects of detector response to low-energy electron energy scale and its resolution including readout electronics threshold effects are quantified. Finally, the relation between the theoretical and reconstructed low-energy electron energy spectra is derived, and the energy resolution is characterized. The low-energy electron selection presented here accounts for about 75% of the total electron deposited energy. After the addition of lost energy using a Monte Carlo simulation, the energy resolution improves from about 40% to 25% at 50 MeV. These results are used to validate the expected capabilities of the DUNE far detector to reconstruct low-energy electrons.

C. Alt

S. Antusch

M. Betancourt

A. Betancur Rodríguez

A. Bevan

Y. Bezawada

A. T. Bezerra

Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector

In this work, we investigate the role of multi-nucleon (MN) effects (mainly 2p-2h and RPA) on the sensitivity measurement of various neutrino oscillation parameters, in the disappearance channel of NOνA (USA) experiment. Short-range correlations and detector effects have also been included in the analysis. We use the kinematical method of reconstruction of the incoming neutrino energy, both at the near and far detectors. The extrapolation technique has been used to estimate oscillated events at the far detector. The latest global best fit values of various light neutrino oscillation parameters have been used in the analysis. We find that MN effects increase uncertainty in the measurement of neutrino oscillation parameters, while lower detector efficiency is reflected in more uncertainty. This study can give useful insight into precision studies at long-baseline neutrino experiments in future measurements.

Neelakshi Sarma

Uncertainties in the oscillation parameters measurement due to multi-nucleon effects at NO A experiment

The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNE’s sensitivity to observe charge-parity violation (CPV) in the neutrino sector, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-calendar years (kt-MW-CY), where calendar years include an assumption of 57% accelerator uptime based on past accelerator performance at Fermilab. The analysis includes detailed uncertainties on the flux prediction, the neutrino interaction model, and detector effects. We demonstrate that DUNE will be able to unambiguously resolve the neutrino mass ordering at a <math><mrow><mn>4</mn><mi>σ</mi></mrow></math> (<math><mrow><mn>5</mn><mi>σ</mi></mrow></math>) level with a 66 (100) kt-MW-CY far detector exposure, and has the ability to make strong statements at significantly shorter exposures depending on the true value of other oscillation parameters, with a median sensitivity of <math><mrow><mn>3</mn><mi>σ</mi></mrow></math> for almost all true <math><msub><mi>δ</mi><mrow><mi>CP</mi></mrow></msub></math> values after only 24 kt-MW-CY. We also show that DUNE has the potential to make a robust measurement of CPV at a <math><mrow><mn>3</mn><mi>σ</mi></mrow></math> level with a 100 kt-MW-CY exposure for the maximally CP-violating values <math><msub><mi>δ</mi><mrow><mi>CP</mi></mrow></msub><mo>=</mo><mo>±</mo><mi>π</mi><mo>/</mo><mn>2</mn></math>. Additionally, the dependence of DUNE’s sensitivity on the exposure taken in neutrino-enhanced and antineutrino-enhanced running is discussed. An equal fraction of exposure taken in each beam mode is found to be close to optimal when considered over the entire space of interest.

B. Ali-Mohammadzadeh

T. Alion

M. AlRashed

C. Backhouse

J. L. Bazo Alba

T. J. C. Bezerra

A. Bhardwaj

Low exposure long-baseline neutrino oscillation sensitivity of the DUNE experiment