12 research outputs found
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Measurement of the ?e-nucleus charged-current double-differential cross section at ?E?? = 2.4 GeV using NOvA
The inclusive electron neutrino charged-current cross section is measured in the NOvA near detector using 8.02×1020 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 ? 17% systematic rather than the ? 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 Q2(squared four-momentum transfer) and energy, in the range 1 GeV = E? < 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. Q2
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Study of quasielastic scattering using charged-current ?µ-iron interactions in the MINOS near detector
Kinematic distributions from an inclusive sample of 1.41 × 10^6 charged-current ?µ interactions on iron, obtained using the MINOS near detector exposed to a wide-band beam with peak flux at 3 GeV, are compared to a conventional treatment of neutrino scattering within a Fermi gas nucleus. Results are used to guide the selection of a subsample enriched in quasielastic ?µFe interactions, containing an estimated 123,000 quasielastic events of incident energies 1 < E? < 8 GeV, with hE?i ¼ 2.79 GeV. Four additional subsamples representing topological and kinematic sideband regions to quasielastic scattering are also selected for the purpose of evaluating backgrounds. Comparisons using subsample distributions in fourmomentum transfer Q^2 show the Monte Carlo model to be inadequate at low Q^2. Its shortcomings are remedied via inclusion of a Q^2-dependent suppression function for baryon resonance production, developed from the data. A chi-square fit of the resulting Monte Carlo simulation to the shape of the Q2 distribution for the quasielastic-enriched sample is carried out with the axial-vector mass MA of the dipole axial-vector form factor of the neutron as a free parameter. The effective MA which best describes the data is 1.23+0.13-0.09 (fit)+0.12-0.15 (syst) GeV
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Search for flavor-changing nonstandard neutrino interactions using ?e appearance in MINOS
We report new constraints on flavor-changing nonstandard neutrino interactions from the MINOS longbaseline experiment using ?e and ¯?e appearance candidate events from predominantly ?µ and ¯?µ beams. We used a statistical selection algorithm to separate ?e candidates from background events, enabling an analysis of the combined MINOS neutrino and antineutrino data. We observe no deviations from standard neutrino mixing, and thus place constraints on the nonstandard interaction matter effect, |eet|, and phase, (dCP + det), using a 30-bin likelihood fit
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Measurement of single p0 production by coherent neutral-current ? Fe interactions in the MINOS Near Detector
Forward single p0 production by coherent neutral-current interactions, ?A ? ?Ap0, is investigated using a 2.8 × 10^20 protons-on-target exposure of the MINOS Near Detector. For single-shower topologies, the event distribution in production angle exhibits a clear excess above the estimated background at very forward angles for visible energy in the range 1–8 GeV. Cross sections are obtained for the detector medium comprised of 80% iron and 20% carbon nuclei with = 48, the highest- target used to date in the study of this coherent reaction. The total cross section for coherent neutral-current single p0 production initiated by the ?µ flux of the NuMI low-energy beam with mean (mode) E? of 4.9 GeV (3.0 GeV), is 77.6±5.0(stat)+15.0-16.8 (syst) × 10-40 cm2 pernucleus. The results are in good agreement with predictions of the Berger-Sehgal model.</a
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Combined analysis of ?µ disappearance and ?µ ? ?e appearance in MINOS using accelerator and atmospheric neutrinos
We report on a new analysis of neutrino oscillations in MINOS using the complete set of accelerator and atmospheric data. The analysis combines the ?µ disappearance and ?e appearance data using the three-flavor formalism. We measure |?m^2 32| = [2.28–2.46] × 10-3 eV^2 (68% C.L.) and sin^2 ?23 = 0.35–0.65 (90% C.L.) in the normal hierarchy, and |?m^2 32| = [2.32–2.53] × 10-3 eV^2 (68% C.L.) and sin^2 ?23 = 0.34–0.67 (90% C.L.) in the inverted hierarchy. The data also constrain dCP, the ?23 octant degeneracy and the mass hierarchy; we disfavor 36% (11%) of this three-parameter space at 68% (90%) C.L
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Measurement of the neutrino mixing angle ?23 in NOvA
This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of 6.05×1020 protons on target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal ?23 mixing (?23=p/4). Assuming the normal mass hierarchy, we find ?m232=(2.67±0.11)×10-3??eV2 and sin2?23 at the two statistically degenerate values 0.404 +0.030-0.022 and 0.624 +0.022-0.030, both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6s significance
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Constraints on oscillation parameters from ?e appearance and ?µ disappearance in NOvA
Results are reported from an improved measurement of ?µ??e transitions by the NOvA experiment. Using an exposure equivalent to 6.05×1020 protons on target, 33 ?e candidates are observed with a background of 8.2±0.8 (syst.). Combined with the latest NOvA ?µ disappearance data and external constraints from reactor experiments on sin22?13, the hypothesis of inverted mass hierarchy with ?23 in the lower octant is disfavored at greater than 93% C.L. for all values of dCP
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Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment
A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the O(10) MeV 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 νe 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 σ(Eν) for charged-current νe absorption on argon. In the context of a simulated extraction of supernova νe spectral parameters from a toy analysis, we investigate the impact of σ(Eν) modeling uncertainties on DUNE's supernova neutrino physics sensitivity for the first time. We find that the currently large theoretical uncertainties on σ(Eν) must be substantially reduced before the νe 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 σ(Eν) 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 σ(Eν). A direct measurement of low-energy νe-argon scattering would be invaluable for improving the theoretical precision to the needed level
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The NuMI neutrino beam
This paper describes the hardware and operations of the Neutrinos at the Main Injector (NuMI) beam at Fermilab. It elaborates on the design considerations for the beam as a whole and for individual elements. The most important design details of individual components are described. Beam monitoring systems and procedures, including the tuning and alignment of the beam and NuMI long-term performance, are also discussed
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Search for muon-neutrino to electron-neutrino transitions in MINOS
This Letter reports on a search for e transitions by the MINOS experiment based on a 3.141020 protons-on-target exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of 275(stat)2(syst) events predicted by the measurements in the Near Detector. If interpreted in terms of e oscillations, this 1.5s excess of events is consistent with sin2(213) comparable to the CHOOZ limit when |m2|=2.4310-3eV2 and sin2(223)=1.0 are assume