24,742 research outputs found
Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam
No full textThis Letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rates and energy spectra of charged current nu(mu) interactions are compared in two detectors located along the beam axis at distances of 1 and 735 km. With 1.27x10(20) 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336 +/- 14 events. The data are consistent with nu(mu) disappearance via oscillations with vertical bar Delta m(32)(2)vertical bar=2.74(-0.26)(+0.44)x10(-3) eV(2) and sin(2)(2 theta(23))> 0.87 (68% C.L.)
Antineutrino Oscillations in the Atmospheric Sector
No full textThis thesis presents measurements of the oscillations of muon antineutrinos in the atmospheric sector, where world knowledge of antineutrino oscillations lags well behind the knowledge of neutrinos, as well as a search for νμ \to ν̅ μ transitions. Differences between neutrino and antineutrino oscillations could be a sign of physics beyond the Standard Model, including non-standard matter interactions or the violation of CPT symmetry. These measurements leverage the sign-selecting capabilities of the magnetized steel-scintillator MINOS detectors to analyze antineutrinos from the NuMI beam, both when it is in FHC and when it is in RHC. Antineutrino oscillations are observed at |Δm̅2atm| = (3.36+0.46-0.40(stat)±0.06(syst)) x 10- eV2 and sin2(2θ̅23 = 0.860+0.11-0.12(stat)± 0.01(syst). The oscillation parameters measured for antineutrinos and those measured by MINOS for neutrinos differ by a large enough margin that the chance of obtaining two values as discrepant as those observed is only 2%, assuming the two measurements arise from the same underlying mechanism, with the same parameter values. No evidence is seen for neutrino-to-antineutrino transitions
Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam
No full textThis letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rate and energy spectra of charged current muon neutrino interactions are compared in two detectors located along the beam axis at distances of 1 km and 735 km. With 1.27 x 10^{20} 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336 \pm 14.4 events. The data are consistent with muon neutrino disappearance via oscillation with |\Delta m^2_{23}| = 2.74^{+0.44}_{-0.26} x 10^{-3} eV^2/c^4 and sin^2(2\theta_{23}) > 0.87 (at 60% C.L.)
Search for flavor-changing nonstandard neutrino interactions using nu(e) appearance in MINOS
No full textWe report new constraints on flavor-changing nonstandard neutrino interactions from the MINOS long-baseline experiment using nu(e) and (nu) over bar (e) appearance candidate events from predominantly nu(mu) and (nu) over bar (mu) beams. We used a statistical selection algorithm to separate nu(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, vertical bar epsilon(e tau)vertical bar, and phase, (delta(CP) + delta(e tau)), using a 30-bin likelihood fit.Physic
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The MINOS Scintillator Calorimeter System
No full textThe MINOS detectors will use extruded plastic scintillator strips, which are read out by wavelength-shifting fibers coupled to multipixel photodetectors. This technique provides excellent energy and spatial resolution. The MINOS detectors are described in detail along with results from light output tests
Observation of seasonal variation of atmospheric multiple-muon events in the MINOS Near and Far Detectors
No full textWe report the first observation of seasonal modulations in the rates of cosmic ray multiple-muon events at two underground sites, the MINOS Near Detector with an overburden of 225 mwe, and the MINOS Far Detector site at 2100 mwe. At the deeper site, multiple-muon events with muons separated by more than 8 m exhibit a seasonal rate that peaks during the summer, similar to that of single-muon events. In contrast and unexpectedly, the rate of multiple-muon events with muons separated by less than 5–8 m, and the rate of multiple-muon events in the smaller, shallower Near Detector, exhibit a seasonal rate modulation that peaks in the winter
Search for flavor-changing nonstandard neutrino interactions using ?e appearance in MINOS
No full textWe 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
Precision constraints for three-flavor neutrino oscillations from the full MINOS+ and MINOS dataset
No full textWe report the final measurement of the neutrino oscillation parameters Δm_{32}^{2} and sin^{2}θ_{23} using all data from the MINOS and MINOS+ experiments. These data were collected using a total exposure of 23.76×10^{20} protons on target producing ν_{μ} and ν[over ¯]_{μ} beams and 60.75 kt yr exposure to atmospheric neutrinos. The measurement of the disappearance of ν_{μ} and the appearance of ν_{e} events between the Near and Far detectors yields |Δm_{32}^{2}|=2.40_{-0.09}^{+0.08}(2.45_{-0.08}^{+0.07})×10^{-3} eV^{2} and sin^{2}θ_{23}=0.43_{-0.04}^{+0.20}(0.42_{-0.03}^{+0.07}) at 68% C.L. for normal (inverted) hierarchy
Constraints on large extra dimensions from the MINOS experiment
No full textWe report new constraints on the size of large extra dimensions from data collected by the MINOS experiment between 2005 and 2012. Our analysis employs a model in which sterile neutrinos arise as Kaluza-Klein states in large extra dimensions and thus modify the neutrino oscillation probabilities due to mixing between active and sterile neutrino states. Using Fermilab’s Neutrinos at the Main Injector beam exposure of 10.56 × 1020 protons on target, we combine muon neutrino charged current and neutral current data sets from the Near and Far Detectors and observe no evidence for deviations from standard three-flavor neutrino oscillations. The ratios of reconstructed energy spectra in the two detectors constrain the size of large extra dimensions to be smaller than 0.45 µm at 90% C.L. in the limit of a vanishing lightest active neutrino mass. Stronger limits are obtained for nonvanishing masses
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Search for flavor-changing nonstandard neutrino interactions using ?e appearance in MINOS
No full textWe 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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