116 research outputs found

    Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam

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    This 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.)

    New Results from the MINOS Experiment

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    In this paper we present the latest results from the MINOS Experiment. This includes a new measurement of the atmospheric neutrino oscillation parameters based on 3.36 x 10^20 protons-on-target of data and a first analysis of neutral current events in the Far Detector. The prospects for nu-e appearance measurements in MINOS are also discussed.Comment: 6 pages, 4 figures, for the Proceedings of the Neutrino 2008 Conference, Christchurch, N

    Precision measurement of the speed of propagation of neutrinos using the MINOS detectors

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    We report a two-detector measurement of the propagation speed of neutrinos over a baseline of 734 km. The measurement was made with the NuMI beam at Fermilab between the near and far MINOS detectors. The fractional difference between the neutrino speed and the speed of light is determined to be (v/c1)=(1.0±1.1)×106(v/c-1) = (1.0 \pm 1.1) \times 10^{-6}, consistent with relativistic neutrinos

    Long term performance of the MINOS calibration procedure and stability of the MINOS detectors

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    The MINOS detectors are steel-scintilla tor sampling tracking calorimeters and are calibrated using an in-situ light-injection system and cosmic ray muons. The MINOS Near and Far Detectors have been operating almost continuously since 2003 and 2005, providing opportunity to quantify the behavior of the various detector components, many of which are used in the next generation neutrino oscillation experiments, under long-term experimental operation. We report, oil the calibration procedure mid its stability, as well as the time aud temperature dependencies of the scintillator, wavelength-shifting fibers and photo-multiplier tubes

    A search for sterile neutrinos mixing with muon neutrinos in MINOS

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    We report results of a search for oscillations involving a light sterile neutrino over distances of 1.04km and 735km in a __-dominated beam with peak energy of 3 GeV. The data, from an exposure of 10:56 _ 1020 protons-on-target, are analyzed using a phenomenological model with one sterile neutrino. We constrain the mixing parameters _24 and _m2 41 and set limits on parameters of the four-dimensional PMNS matrix, jU_4j2 and jU_4j2, under the assumption that mixing between _e and _s is negligible (jUe4j2 = 0). No evidence for __ ! _s transitions is found and we set a world-leading limit on _24 for values of _m2 41 . 1 eV2

    A search for flavor-changing non-standard neutrino interactions using νeν_{e} appearance in MINOS

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    We report new constraints on flavor-changing non-standard neutrino interactions from the MINOS long-baseline experiment using νe\nu_{e} appearance candidate events from a predominantly νμ\nu_{\mu} beam. We used a statistical selection algorithm to separate νe\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 non-standard interaction matter effect, εeτ\varepsilon_{e\tau}, and phase, (δCP+δeτ)(\delta_{CP}+\delta_{e\tau}), using a thirty-bin likelihood fit

    Observation of muon intensity variations by season with the MINOS Near Detector

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    A sample of 1.53×\times109^{9} cosmic-ray-induced single muon events has been recorded at 225 meters-water-equivalent using the MINOS Near Detector. The underground muon rate is observed to be highly correlated with the effective atmospheric temperature. The coefficient αT\alpha_{T}, relating the change in the muon rate to the change in the vertical effective temperature, is determined to be 0.428±\pm0.003(stat.)±\pm0.059(syst.). An alternative description is provided by the weighted effective temperature, introduced to account for the differences in the temperature profile and muon flux as a function of zenith angle. Using the latter estimation of temperature, the coefficient is determined to be 0.352±\pm0.003(stat.)±\pm0.046(syst.)

    Global neutrino data and recent reactor fluxes: status of three-flavour oscillation parameters

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    We present the results of a global neutrino oscillation data analysis within the three-flavour framework. We include latest results from the MINOS long-baseline experiment (including electron neutrino appearance as well as anti-neutrino data), updating all relevant solar (SK II+III), atmospheric (SK I+II+III) and reactor (KamLAND) data. Furthermore, we include a recent re-calculation of the anti-neutrino fluxes emitted from nuclear reactors. These results have important consequences for the analysis of reactor experiments and in particular for the status of the mixing angle θ13\theta_{13}. In our recommended default analysis we find from the global fit that the hint for non-zero θ13\theta_{13} remains weak, at 1.8σ\sigma for both neutrino mass hierarchy schemes. However, we discuss in detail the dependence of these results on assumptions concerning the reactor neutrino analysis.Comment: 15 pages, 10 figures and 2 tables, v2: corrected version, main conclusions unchanged, references adde

    Neutrino Beams From Electron Capture at High Gamma

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    We investigate the potential of a flavor pure high gamma electron capture electron neutrino beam directed towards a large water cherenkov detector with 500 kt fiducial mass. The energy of the neutrinos is reconstructed by the position measurement within the detector and superb energy resolution capabilities could be achieved. We estimate the requirements for such a scenario to be competitive to a neutrino/anti-neutrino running at a neutrino factory with less accurate energy resolution. Although the requirements turn out to be extreme, in principle such a scenario could achieve as good abilities to resolve correlations and degeneracies in the search for sin^2(2 theta_13) and delta_CP as a standard neutrino factory experiment.Comment: 21 pages, 7 figures, revised version, to appear in JHEP, Fig.7 extended, minnor changes, results unchange