Deep Underground Neutrino Experiment Research Articles

Tau neutrinos at DUNE: New strategies, new opportunities

We propose a novel analysis strategy, that leverages the unique capabilities of the DUNE experiment, to study tau neutrinos. We integrate collider physics ideas, such as jet clustering algorithms in combination with machine learning techniques, into neutrino measurements. Through the construction of a set of observables and kinematic cuts, we obtain a superior discrimination of the signal ($S$) over the background ($B$). In a single year, using the nominal neutrino beam mode, DUNE may achieve $S/\sqrt{B}$ of $3.3$ and $2.3$ for the hadronic and leptonic decay channels of the tau respectively. Operating in the tau-optimized beam mode would increase $S/\sqrt{B}$ to $8.8$ and $11$ for each of these channels. We premier the use of the analysis software Rivet, a tool ubiquitously used by the LHC experiments, in neutrino physics. For wider accessibility, we provide our analysis code.

A global analysis strategy to resolve neutrino NSI degeneracies with scattering and oscillation data

Neutrino non-standard interactions (NSI) with the first generation of standard model fermions can span a parameter space of large dimension and exhibit degeneracies that cannot be broken by a single class of experiment. Oscillation experiments, together with neutrino scattering experiments, can merge their observations into a highly informational dataset to combat this problem. We consider combining neutrino-electron and neutrino-nucleus scattering data from the Borexino and COHERENT experiments, including a projection for the upcoming coherent neutrino scattering measurement at the CENNS-10 liquid argon detector. We extend the reach of these data sets over the NSI parameter space with projections for neutrino scattering at a future multi-ton scale dark matter detector and future oscillation measurements from atmospheric neutrinos at the Deep Underground Neutrino Experiment (DUNE). In order to perform this global anal- ysis, we adopt a novel approach using the copula method, utilized to combine posterior information from different experiments with a large, generalized set of NSI parameters. We find that the contributions from DUNE and a dark matter detector to the Borexino and COHERENT fits can improve constraints on the electron and quark NSI parameters by up to a factor of 2 to 3, even when relatively many NSI parameters are left free to vary in the analysis.

Dark matter detection capabilities of a large multipurpose Liquid Argon Time Projection Chamber

Liquid Argon Time Projection Chambers are planned to comprise a central role in the future of the U.S. High Energy Physics neutrino program. In particular, this detector technology will form the basis for the 40 kton Deep Underground Neutrino Experiment (DUNE) . In this paper we take as a starting point the dual phase far detector design proposed by the DUNE experiment and ask what changes are necessary to allow one of the four 10 kt modules to be sensitive to heavy Weakly Interacting Massive Particle (WIMP) dark matter. We show that with control over backgrounds and the use of low radioactivity argon, which may be commercially available on that timescale, along with a significant increase in light detection, one DUNE-like module gives a competitive WIMP detection sensitivity, particularly above a dark matter mass of 100 GeV.

First testing of the Hamamatsu R5912-02Mod photomultiplier tube at 4-bar pressure and cryogenic temperature

The Hamamatsu R5912-02Mod photomultiplier tube (PMT) will be used in the DUNE dual-phase module, a 10-kton fiducial volume liquid-argon time-projection chamber, which is one of the four projected far-detector modules of the DUNE long-baseline neutrino experiment. In the DUNE dual-phase module, the liquid argon places high pressure on the photo-detectors located at the bottom of the 14-m cryostat. Four Hamamatsu R5912-02Mod PMTs were tested at 4-bar absolute pressure and cryogenic temperature (in liquid nitrogen) for the first time. No mechanical or electrical damage is reported, validating the use of this PMT model in the DUNE dual-phase module and in other large scale cryogenic liquid detectors. The differences observed in their behavior are expected for the change in the PMT operating temperature.

Neutrino-hydrogen interactions with a high-pressure time projection chamber

We investigate the idea of detecting pure neutrino-hydrogen interactions in a multinuclear target using the transverse kinematic imbalance technique [Lu et al., Phys. Rev. D 92, 051302 (2015)] in a high-pressure time projection chamber (HPTPC). With full solid-angle acceptance, MeV-level proton tracking threshold, state-of-the-art tracking resolution, and an O(100 m^3) gas volume at 10 bar, an HPTPC could provide an opportunity to realize this technique. We propose the use of hydrogen-rich gases in the TPC to achieve high detection purity with large hydrogen mass. With the projected neutrino beam exposure at the DUNE experiment, neutrino-hydrogen events of the order of 10^4 per year with purity above 90% could be achieved with such an HPTPC using methane gas. In this paper, we present a systematic study of the event rate and purity for a variety of argon-alkane mixtures, and examine these gas candidates for the TPC tracking-related properties.

Neutrino phenomenology in a left-right D4 symmetric model

We present a minimal left-right symmetric flavor model and analyze the predictions for the neutrino sector. In this scenario, the Yukawa sector is shaped by the dihedral $D_4$ symmetry which leads to correlations for the neutrino mixing parameters. We end up with four possible solutions within this model. We further analyzed the impact of the upcoming long-baseline neutrino oscillation experiment DUNE. Due to its high sensitivity, DUNE will be able to rule out two of the solutions. Finally, the prediction for the neutrinoless double beta decay for the model has also been examined.

Volume I. Introduction to DUNE

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE's physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology.

Volume III. DUNE far detector technical coordination

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume III of this TDR describes how the activities required to design, construct, fabricate, install, and commission the DUNE far detector modules are organized and managed. This volume details the organizational structures that will carry out and/or oversee the planned far detector activities safely, successfully, on time, and on budget. It presents overviews of the facilities, supporting infrastructure, and detectors for context, and it outlines the project-related functions and methodologies used by the DUNE technical coordination organization, focusing on the areas of integration engineering, technical reviews, quality assurance and control, and safety oversight. Because of its more advanced stage of development, functional examples presented in this volume focus primarily on the single-phase (SP) detector module.

Can Lorentz invariance violation affect the sensitivity of deep underground neutrino experiment?

We examine the impact of Lorentz Invariance Violation (LIV) in measuring the octant of theta _{23} and CP phases in the context of the Deep Underground Neutrino Experiment (DUNE). We consider the CPT-violating LIV parameters involving e - mu (a_{emu }) and e - tau (a_{etau }) flavors, which induce an additional interference term in neutrino and antineutrino appearance probabilities. This new interference term depends on both the standard CP phase delta and the new dynamical CP phase varphi _{emu }/varphi _{etau }, giving rise to new degeneracies among (theta _{23}, delta , varphi ). Taking one LIV parameter at-a-time and considering a small value of |a_{emu }| = |a_{etau }| = 5 times 10^{-24} GeV, we find that the octant discovery potential of DUNE gets substantially deteriorated for unfavorable combinations of delta and varphi _{emu }/varphi _{etau }. The octant of theta _{23} can only be resolved at 3sigma if the true value of sin ^2theta _{23} lesssim 0.42 or > rsim 0.62 for any choices of delta and varphi . Interestingly, we also observe that when both the LIV parameters a_{emu } and a_{etau } are present together, they cancel out the impact of each other to a significant extent, allowing DUNE to largely regain its octant resolution capability. We also reconstruct the CP phases delta and varphi _{emu }/varphi _{etau }. The typical 1sigma uncertainty on delta is 10–15^{circ } and the same on varphi _{emu }/varphi _{etau } is 25–30^{circ } depending on the choices of their true values.

Measuring the Weak Mixing Angle in the DUNE Near-Detector Complex.

The planned DUNE experiment will have excellent sensitivity to the vector and axial couplings of the electron to the Z boson via precision measurements of neutrino-electron scattering. We investigate the sensitivity of DUNE-PRISM, a movable near detector in the direction perpendicular to the beam line, and find that it will qualitatively impact our ability to constrain the weak couplings of the electron. We translate these neutrino-electron scattering measurements into a determination of the weak mixing angle at low scales and estimate that, with seven years of data taking, the DUNE near detector can be used to measure sin^{2}θ_{W} with about 2% precision. We also discuss the impact of combining neutrino-electron scattering data with neutrino trident production at DUNE-PRISM.

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.

Scalable deep convolutional neural networks for sparse, locally dense liquid argon time projection chamber data

Deep convolutional neural networks (CNNs) show strong promise for analyzing scientific data in many domains including particle imaging detectors such as a liquid argon time projection chamber (LArTPC). Yet the high sparsity of LArTPC data challenges traditional CNNs which were designed for dense data such as photographs. A naive application of CNNs on LArTPC data results in inefficient computations and a poor scalability to large LArTPC detectors such as the Short Baseline Neutrino Program and Deep Underground Neutrino Experiment. Recently Submanifold Sparse Convolutional Networks (SSCNs) have been proposed to address this challenge. We report their performance on a 3D semantic segmentation task on simulated LArTPC samples. In comparison with standard CNNs, we observe that the computation memory and wall-time cost for inference are reduced by factor of 364 and 33 respectively without loss of accuracy. The same factors for 2D samples are found to be 93 and 3.1 respectively. Using SSCN, we present the first machine learning-based approach to the reconstruction of Michel electrons using public 3D LArTPC samples. We find a Michel electron identification efficiency of 93.9% with 96.7% of true positive rate. Reconstructed Michel electron clusters yield 95.4% in average pixel clustering efficiency and 95.5% in purity. The results are compelling to show strong promise of scalable data reconstruction technique using deep neural networks for large scale LArTPC detectors.

Development of the Light Collection Module for the Liquid Argon Time Projection Chamber (LArTPC)

A modular liquid argon (LAr) Time Projection Chamber (TPC) with pixelated charge readout is considered as a part of the near-detector for the Deep Underground Neutrino Experiment (DUNE) [1]. Such a TPC is being developed by the ArgonCube collaboration [2]. To provide a trigger for the data acquisition (DAQ) of a neutrino event the LAr scintillation light detection is proposed. The light is a vacuum ultraviolet (UV) with 128 nm wavelength, thus, it is a challenge to register it. The main requirements imposed on the light detection system are a good performance at cryogenic temperatures, non-conductive materials, compact dimensions, and a detection efficiency at a level of percent. A Light Collection Module (LCM) as a candidate for the system has been developed at Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The LCM is based on the wavelength-shifting (WLS) fibers that are coated with Tetraphenyl Butadiene (TPB) and read out by silicon photomultipliers (SiPM). Also at JINR, a full readout chain for the light detection system has been developed, consisting of the front-end electronics, power-supply for the SiPMs, and the DAQ. A cryogenic test setup has been built at JINR to study the performance of the LCM in LAr. A similar study was carried out in the laboratory for high energy physics of Bern University with highly purified LAr. These studies have shown that the photon detection efficiency (PDE) of the LCM for the LAr scintillation light is about 1–2%. Further tests in the ArgonCube prototype TPC will provide the real performance of the LCM system with a full readout chain.

New 3D fine-grained scintillation detector for the T2K experiment

The main goal of the T2K long-baseline neutrino experiment is the precise measurement of the parameters of neutrino oscillation and the search for CP-violation in the lepton sector. In 2017, the T2K collaboration launched the Near Detector Upgrade project. This upgrade aims to reduce the systematic errors of the oscillation parameters from 6–7% to 3–4%. In order to accomplish such goal, ND280 Upgrade proposes to implement new upstream trackers to improve the wide angle acceptance and low momentum threshold. One of the novel technologies introduced in ND280 Upgrade is super fine-grained (SuperFGD) scintillator target with 3D WLS fiber readout. The detector will consist of about 2 million (192× 184× 56) scintillation cubes of 1-cm size. Each cube has three orthogonal holes for WLS fibers to provide 3D optical readout. The total mass of the detector is about 2 tons and the number of the readout channels is about 60,000. This paper presents the current status of the development of this detector.

Probing the predictions of an orbifold theory of flavor

We examine the implications of a recently proposed theory of fermion masses and mixings in which an ${A}_{4}$ family symmetry emerges from orbifold compactification. We analyze two variant schemes concerning their predictions for neutrino oscillations, neutrinoless double-beta decay, and the golden quark-lepton unification mass relation. We find that upcoming experiments DUNE as well as LEGEND and nEXO offer good chances of exploring a substantial region of neutrino parameters.

Analysis of the light production and propagation in the 4-tonne dual-phase demonstrator

The Deep Underground Neutrino Experiment (DUNE) is a leading-edge experiment designed to perform neutrino science and proton decay searches. In particular, the far detector will consist of four 10-kton Liquid Argon (LAr) Time Projection Chambers using both single and dual-phase technologies. The latter provides charge amplification in the gaseous phase. In order to optimize these designs, two large prototypes are taking data at CERN since 2018. Previously, a dual-phase 4-tonne demonstrator was constructed and exposed to cosmic muons in 2017 and exhibited good performance in terms of charge and light collection. The light detection system is important to provide a trigger to the charge acquisition system and to obtain additional information from the scintillation light produced in the particle interaction. In the demonstrator, five cryogenic photo-multipliers were installed with different base polarity configurations and wavelength shifting methods. During the detector operation, scintillation light data were collected in different drift and amplification field conditions. An overview of the light detection system performance and results on the light production and propagation are presented. Our studies allowed us to improve the understanding of some LAr properties.

The ProtoDUNE-SP LArTPC electronics production, commissioning, and performance

The ProtoDUNE-SP detector is a large-scale prototype of the Single-Phase (SP) Liquid Argon Time Projection Chamber (LArTPC) design proposed for the Deep Underground Neutrino Experiment (DUNE). 15,360 LArTPC wires are instrumented with low electronic noise pre-amplifier and digitization ASICs integrated into Front End Motherboards (FEMBs) operating at cryogenic temperature within the cryostat. The large number of electronics channels and high performance specifications required a large-scale production electronics quality control effort, careful installation into Anode Plane Assemblies (APAs), and rigorous detector commissioning. This successful collaboration-wide effort achieved a working LArTPC electronics channel percentage of 99.7% (15,318 of 15,360 channels in total), whose operating performance exceeded expectations. We summarize the ProtoDUNE-SP cold electronics design and quality control, installation, and commissioning efforts that enabled this excellent electronics performance.

A measurement of absolute efficiency of the ARAPUCA photon detector in liquid argon

In the Fall of 2017, two photon detector designs for the Deep Underground Neutrino Experiment (DUNE) Far Detector were installed and tested in the TallBo liquid argon (LAr) cryostat at the Proton Assembly (PAB) facility, Fermilab. The designs include two light bars developed at Indiana University and a photon detector based on the ARAPUCA light trap engineered by Colorado State University and Fermilab. The performance of these devices is determined by analyzing 8 weeks of cosmic ray data. The current paper focuses solely on the ARAPUCA device as the performance of the light bars will be reported separately. The paper briefly describes the ARAPUCA concept, the TallBo setup, and focuses on data analysis and results.

Prospects of light sterile neutrino searches in long-baseline neutrino oscillations

The neutrino oscillation probabilities in vacuum and matter are discussed, considering the framework of three active and one light sterile neutrinos. We study in detail the rephasing invariants and CP asymmetry observables, and investigate the four-neutrino oscillations in long-baseline neutrino experiments, such as DUNE, NOνA and T2HK. Our results show that the matter effect enhances quite a significantly the oscillation probabilities of electron neutrino and electron antineutrino appearance channels within a certain energy range, while no considerable change arises in the CP asymmetry analysis due to the matter effect. Moreover, separation between the results with and without the sterile neutrino is not so significant and that is also affected by CP-violating phases. Comparing the results for these three experiments, all of them have similar features, nevertheless, sizes and separations of the oscillation probabilities in DUNE are bit larger.

JINR stand measurements for improvements in the NOvA detector simulation chain

The NOvA [1] (NuMI Off-axis νe Appearance) is a long-baseline neutrino experiment studying neutrino oscillation phenomenon in the muon neutrino beam. The apparatus consists of a Near Detector at the Fermilab (U.S.A.) site, where the neutrinos are produced by the NuMI facility, and a Far Detector placed 810 km away. Both detectors are of similar construction based on a large-volume liquid scintillator tracking calorimeter with a finely segmented structure. Two test stands have been built at JINR (Dubna, Russia) to measure the Birks constant for protons of NOvA scintillator and the signal shaping of the NOvA electronics. During the years of the NOvA experiment operation, a comprehensive understanding of the NOvA detectors' performance was achieved, in particular, due to important additional measurements of electronics and scintillator parameters performed at the test benches. The parameters measured using these test stands have been implemented in the custom NOvA simulation chain.