152 research outputs found

    Seasonal Variation of Multiple-Muon Cosmic Ray Air Showers Observed in the NOvA Detector on the Surface

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    We report the rate of cosmic ray air showers with multiplicities exceeding 15 muon tracks recorded in the NOvA Far Detector between May 2016 and May 2018. The detector is located on the surface under an overburden of 3.6 meters water equivalent. We observe a seasonal dependence in the rate of multiple-muon showers, which varies in magnitude with multiplicity and zenith angle. During this period, the effective atmospheric temperature and surface pressure ranged between 210 K to 230 K and 940mbar to 990mbar, respectively; the shower rates are anti-correlated with the variation in the effective temperature. The variations are about 30% larger for the highest multiplicities than the lowest multiplicities and 20% larger for showers near the horizon than vertical showers

    An Improved Measurement of Neutrino Oscillation Parameters by the NOvA Experiment

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    We present new ΜΌ→Μe\nu_\mu\rightarrow\nu_e, ΜΌ→ΜΌ\nu_\mu\rightarrow\nu_\mu, Μ‟Ό→Μ‟e\overline{\nu}_\mu\rightarrow\overline{\nu}_e, and Μ‟Ό→Μ‟Ό\overline{\nu}_\mu\rightarrow\overline{\nu}_\mu oscillation measurements by the NOvA experiment, with a 50% increase in neutrino-mode beam exposure over the previously reported results. The additional data, combined with previously published neutrino and antineutrino data, are all analyzed using improved techniques and simulations. A joint fit to the Îœe\nu_e, ΜΌ\nu_\mu, Μ‟e\overline{\nu}_e, and Μ‟Ό\overline{\nu}_\mu candidate samples within the 3-flavor neutrino oscillation framework continues to yield a best-fit point in the normal mass ordering and the upper octant of the Ξ23\theta_{23} mixing angle, with Δm322=(2.41±0.07)×10−3\Delta m^{2}_{32} = (2.41\pm0.07)\times 10^{-3} eV2^2 and sin⁥2Ξ23=0.57−0.04+0.03\sin^2\theta_{23} = 0.57^{+0.03}_{-0.04}. The data disfavor combinations of oscillation parameters that give rise to a large asymmetry in the rates of Îœe\nu_e and Μ‟e\overline{\nu}_e appearance. This includes values of the CP-violating phase in the vicinity of ÎŽCP=π/2\delta_\text{CP} = \pi/2 which are excluded by >3σ>3\sigma for the inverted mass ordering, and values around ÎŽCP=3π/2\delta_\text{CP} = 3\pi/2 in the normal ordering which are disfavored at 2σ\sigma confidence.Comment: 11 pages, 6 figures. Supplementary material attached (7 figures

    Measurement of the Double-Differential Muon-neutrino Charged-Current Inclusive Cross Section in the NOvA Near Detector

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    We report cross-section measurements of the final-state muon kinematics for \numu charged-current interactions in the NOvA near detector using an accumulated 8.09×1020\times10^{20} protons-on-target (POT) in the NuMI beam. We present the results as a double-differential cross section in the observed outgoing muon energy and angle, as well as single-differential cross sections in the derived neutrino energy, EÎœE_\nu, and square of the four-momentum transfer, Q2Q^2. We compare the results to inclusive cross-section predictions from various neutrino event generators via χ2\chi^2 calculations using a covariance matrix that accounts for bin-to-bin correlations of systematic uncertainties. These comparisons show a clear discrepancy between the data and each of the tested predictions at forward muon angle and low Q2Q^2, indicating a missing suppression of the cross section in current neutrino-nucleus scattering models

    Extended search for supernova-like neutrinos in NOvA coincident with LIGO/Virgo detections

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    A search is performed for supernova-like neutrino interactions coincident with 76 gravitational wave events detected by the LIGO/Virgo Collaboration. For 40 of these events, full readout of the time around the gravitational wave is available from the NOvA Far Detector. For these events, we set limits on the fluence of the sum of all neutrino flavors of F<7(4)×1010cm−2F < 7(4)\times 10^{10}\mathrm{cm}^{-2} at 90% C.L. assuming energy and time distributions corresponding to the Garching supernova models with masses 9.6(27)M⊙\mathrm{M}_\odot. Under the hypothesis that any given gravitational wave event was caused by a supernova, this corresponds to a distance of r>29(50)r > 29(50)kpc at 90% C.L. Weaker limits are set for other gravitational wave events with partial Far Detector data and/or Near Detector data.Comment: 10 pages, 2 figure

    Measurement of the Îœe−\nu_e-Nucleus Charged-Current Double-Differential Cross Section at <EÎœ>=\left< E_{\nu} \right> = 2.4 GeV using NOvA

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    The inclusive electron neutrino charged-current cross section is measured in the NOvA near detector using 8.02×10208.02\times10^{20} protons-on-target (POT) in the NuMI beam. The sample of GeV electron neutrino interactions is the largest analyzed to date and is limited by ≃\simeq 17\% systematic rather than the ≃\simeq 7.4\% statistical uncertainties. The double-differential cross section in final-state electron energy and angle is presented for the first time, together with the single-differential dependence on Q2Q^{2} (squared four-momentum transfer) and energy, in the range 1 GeV ≀EÎœ< \leq E_{\nu} < 6 GeV. Detailed comparisons are made to the predictions of the GENIE, GiBUU, NEUT, and NuWro neutrino event generators. The data do not strongly favor a model over the others consistently across all three cross sections measured, though some models have especially good or poor agreement in the single differential cross section vs. Q2Q^{2}

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

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    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-years (kt-MW-yr). 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 3σ\sigma (5σ\sigma) level, with a 66 (100) kt-MW-yr far detector exposure, and has the ability to make strong statements at significantly shorter exposures depending on the true value of other oscillation parameters. We also show that DUNE has the potential to make a robust measurement of CPV at a 3σ\sigma level with a 100 kt-MW-yr exposure for the maximally CP-violating values \delta_{\rm CP}} = \pm\pi/2. 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

    First results on ProtoDUNE-SP liquid argon time projection chamber performance from a beam test at the CERN Neutrino Platform

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    The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of 7.2× 6.1× 7.0 m3. It is installed at the CERN Neutrino Platform in a specially-constructed beam that delivers charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV/c to 7 GeV/c. Beam line instrumentation provides accurate momentum measurements and particle identification. The ProtoDUNE-SP detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment, and it incorporates full-size components as designed for that module. This paper describes the beam line, the time projection chamber, the photon detectors, the cosmic-ray tagger, the signal processing and particle reconstruction. It presents the first results on ProtoDUNE-SP\u27s performance, including noise and gain measurements, dE/dx calibration for muons, protons, pions and electrons, drift electron lifetime measurements, and photon detector noise, signal sensitivity and time resolution measurements. The measured values meet or exceed the specifications for the DUNE far detector, in several cases by large margins. ProtoDUNE-SP\u27s successful operation starting in 2018 and its production of large samples of high-quality data demonstrate the effectiveness of the single-phase far detector design

    Long-baseline neutrino oscillation physics potential of the DUNE experiment

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    The sensitivity of the Deep Underground Neutrino Experiment (DUNE) to neutrino oscillation is determined, based on a full simulation, reconstruction, and event selection of the far detector and a full simulation and parameterized analysis of the near detector. Detailed uncertainties due to the flux prediction, neutrino interaction model, and detector effects are included. DUNE will resolve the neutrino mass ordering to a precision of 5σ, for all ΑCP values, after 2 years of running with the nominal detector design and beam configuration. It has the potential to observe charge-parity violation in the neutrino sector to a precision of 3σ (5σ) after an exposure of 5 (10) years, for 50% of all ΑCP values. It will also make precise measurements of other parameters governing long-baseline neutrino oscillation, and after an exposure of 15 years will achieve a similar sensitivity to sin22Ξ13 to current reactor experiments

    A Gaseous Argon-Based Near Detector to Enhance the Physics Capabilities of DUNE

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    This document presents the concept and physics case for a magnetized gaseous argon-based detector system (ND-GAr) for the Deep Underground Neutrino Experiment (DUNE) Near Detector. This detector system is required in order for DUNE to reach its full physics potential in the measurement of CP violation and in delivering precision measurements of oscillation parameters. In addition to its critical role in the long-baseline oscillation program, ND-GAr will extend the overall physics program of DUNE. The LBNF high-intensity proton beam will provide a large flux of neutrinos that is sampled by ND-GAr, enabling DUNE to discover new particles and search for new interactions and symmetries beyond those predicted in the Standard Model
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