Session P07: Neutrino Experiment I

Pandora automated pattern recognition for LArTPC event reconstruction at DUNE

The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino oscillation experiment with the main goal of measuring CP-violation in the neutrino sector and unambiguously determining neutrino mass hierarchy, as part of a broad research programme. The DUNE Far Detector will employ four high-granularity Liquid-Argon Time-Projection Chambers (LArTPCs) to produce photographic-quality images of neutrino interactions. A crucial step is then the analysis of these images, using advanced pattern-recognition techniques to reconstruct the visible particles in often complex topologies. Automated event reconstruction with the Pandora Software Development Kit fully harnesses the LArTPC imaging capabilities thanks to a multi-algorithm paradigm, integrating traditional pattern recognition with novel machine-learning approaches. This talk provides an overview of the techniques employed in Pandora for event reconstruction at DUNE, and discusses approaches to tune the reconstruction for DUNE's different physics goals.   

First Physics Studies with DUNE Near Detector Prototype (2x2)

The Near Detector (ND) of the Deep Underground Neutrino Experiment (DUNE) allows high-statistics characterization of the DUNE beam close to the source. It is important to understand the capabilities of DUNE ND at the prototyping stage. The DUNE ND Liquid Argon Time Projection Chamber (LArTPC) prototype, known as the "2x2",  is scheduled to begin data taking early in 2024, using the NuMi beam. Initial analysis goals include the measurement of the number of all charged particle tracks, both with and without a pion in the final state, and the first measurement of final state particles in inclusive charged-current (CC) muon-antineutrino scattering. Ongoing simulation and reconstruction studies will be described with the goal of selecting CC anti-neutrino events and their charged final state particles in the detector. These measurements will demonstrate the capabilities of the LArTPC of DUNE's ND and will help developing event simulation and reconstruction techniques for the first round of DUNE analysis.   

Repurposing MINERvA for a DUNE Near Detector Prototype

The Deep Underground Neutrino Detector (DUNE) is the United States' next-generation flagship neutrino oscillation experiment. DUNE will help answer questions about our universe ranging from the matter antimatter asymmetry to whether protons can decay. As part of DUNE's extensive R&D program, the 2x2 demonstrator, a prototype liquid argon time projection chamber (LArTPC) for DUNE's near detector complex, is being run at the NuMI neutrino beamline at Fermi National Accelerator Laboratory (FNAL). The 2x2 is a proof of concept of numerous newly developed detector technologies, including the first demonstration of a pixelated & modular LArTPC. In addition to its technical demonstrations, the 2x2 will be a capable neutrino experiment in its own right. In order to support these measurements we have re-installed and re-configured the MINERvA detector, which took data at FNAL from 2010 to 2019. MINERvA, a solid plastic scintillator detector, will primarily serve as a muon spectrometer for the primary 2x2 LArTPC but will also be capable of limited calorimetry and energy profile measurements. These additional data supplement those collected by the main 2x2 and provide critical information for each neutrino interaction, significantly improving our ability to make cross-section measurements. Re-installation was completed at the end of 2022, and an ongoing campaign of re-calibration and re-validation of the various MINERvA components is underway. MINERvA for 2x2, or Mx2 for short, is also the first component of the 2x2 prototype (and also DUNE as a whole) to have taken neutrino beam data, shown here in preliminary event displays.   

NA61/SHINE Hadron Production Measurements for Accelerator-Based Neutrino Beams

Long-baseline neutrino experiments, such as NOvA, T2K, and DUNE, are working to measure neutrino oscillaCon parameters and will benefit from reduced neutrino flux uncertainCes. The dominant source of neutrino flux uncertainty arises from an insufficient knowledge of parent hadron yields from neutrino producCon targets. Using external hadron producCon measurements, we can significantly reduce these flux uncertainCes. The NA61/SHINE experiment at CERN provides measurements of many hadronic interacCons for this purpose. Recent results from NA61, including 120 GeV incident proton measurements relevant to NuMI and DUNE, will be discussed, as well as progress on a measurement of hadron yields from a NuMI replica target.   

Energy Estimation for the NOvA 3 Flavor Neutrino Oscillation Analysis

NOvA is a long baseline neutrino experiment with a main goal of measuring neutrino oscillation parameters by observing electron neutrino appearance and muon neutrino disappearance. NOvA utilizes the NuMI beam located at Fermilab and two functionally identical detectors: a near detector at Fermilab, and a far detector 810 km away in Ash River, Minnesota. NOvA's detectors measure the electromagnetic and hadronic energy of neutrino events. Neutrino oscillations are a function of energy, so in order to make precise measurements of the oscillation parameters, NOvA must have robust energy estimation with good resolution to accurately resolve the neutrino energy spectra, for both electron and muon neutrinos. This talk will discuss the performance and new improvements of the energy estimators, including advances using machine learning techniques.   

Electromagnetic Response Studies in the NOvA Test Beam

The NOvA Test Beam Program began data taking in 2019 with the purpose of improving the physics reach of the NOvA experiment. The Test Beam utilized a smaller NOvA detector using identical technology to that found in the NOvA experiment's near and far detectors, preceded by beamline instruments capable of providing precise measurements of particle momenta and species. This experimental setup was exposed to a 0.4 - 1.8 GeV /c beam of protons, kaons, pions, muons, and electrons (both charge signs). In this talk, I will discuss the Test Beam electron analyses, which measure electromagnetic response, efficiency, reconstruction, and modeling of electron interactions within the NOvA detector. These analyses are important because they will improve our knowledge of NOvA's systematic uncertainties for the electron neutrino appearance measurement. These measurements will help elucidate the neutrino mass ordering and constrain the parameter space for leptonic CP violation.   

PROSPECT-I Measurement of Absolute Reactor Antineutrino Flux

The Precision Reactor Oscillation and SPECTrum (PROSPECT) experiment is a short-baseline reactor experiment designed to measure the spectrum of antineutrinos and search for evidence of short baseline sterile neutrino oscillations. From 2018 to 2019, the first-generation detector, PROSPECT-I, took data while located roughly 7 m from the High Flux Isotope Reactor (HFIR), an 85 MW, compact core, highly enriched research reactor at Oak Ridge National Laboratory (ORNL). PROSPECT-I was a segmented ⁶Li-loaded liquid scintillator detector which detected neutrinos via inverse beta decay (IBD) events, by detecting the scintillation light of the IBD positron and other particles produced when the IBD neutron captured on the ⁶Li. PROSPECT-I has demonstrated the highest signal-to-background ratio of any surface antineutrino detector with minimal overburden, placing stringent limits on eV scale sterile neutrino oscillations, setting new direct limits on boosted dark matter models, and providing one of the most precise measurements to date of the ²³⁵U antineutrino spectrum. This talk will present ongoing work by the PROSPECT collaboration towards making an absolute flux measurement of the reactor antineutrinos, and detail ongoing work on measuring the detector’s neutron detection efficiency. A significant focus of this work is calculating inefficiencies caused by the fraction of neutrons capturing on targets other than ⁶Li.   

Joint-Search for Light Sterile Neutrino Oscillations by PROSPECT, STEREO, and Daya Bay

The PROSPECT, STEREO, and Daya Bay experiments have provided world-leading results regarding the detection of reactor-produced antineutrinos. PROSPECT and STEREO have made short-baseline (~10m) measurements of antineutrinos from highly enriched uranium (HEU) research reactors where over 99% of the antineutrino flux comes from ²³⁵U. The Daya Bay experiment has studied antineutrino emission at low-enriched uranium (LEU) power reactors that use a mixture of fissile isotopes, with detectors spanning a much larger baseline from the reactor cores (~2km). All three experiments have performed independent searches for sterile neutrino oscillations, excluding different regions of oscillation phase space. A new collaborative effort, utilizing the final data sets from all three experiments, aims to improve the precision of the search for light sterile neutrinos beyond what would be achievable by each experiment individually. In particular, the combination of information from two HEU-based and one LEU-based experiment could extend the phase space coverage in large ∆m² > 10 eV² regions. This presentation reports the current status of the joint oscillation analysis between these experiments.   

Energy calibration of the MONUMENT's HPGe detectors during the 136Ba and 76Se runs

MONUMENT (Muon Ordinary capture for NUclear Matrix elemENT) measures Ordinary Muon Capture (OMC) on isotopes relevant for the neutrinoless double-beta decay (0νββ) searches. The uncertainty of the 0νββ nuclear matrix elements (NMEs) may limit the ability of next-generation searches to probe the effective Majorana neutrino masses down to the claimed few tens of meV. OMC is useful tool to study the 0νββ NMEs as it involves similar momentum transfers and allows one to experimentally probe the virtual transitions involved in the decay. To achieve its goals, MONUMENT needs to precisely reconstruct energy and intensity of the OMC-related gamma emission. In this talk, the energy calibration method using γs from calibration and background sources and ¹³⁶Ba muonic X-rays measured during the 2021 campaign at the PSI will be presented. The energy resolution and time stability studies will also be described. The talk will conclude by discussing the status and outlook of the total and partial capture rate analysis for ¹³⁶Ba and ⁷⁶Se, isotopes relevant for the two next-generation 0νββ searches, nEXO and LEGEND.