Charged-Current ̄µ ν MINOS Disappearance Analysis … · Combined Beam+Atmospherics...

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Date 2005/04/29 2006/03/15 2007/01/29 2007/12/15 2008/10/31 2009/09/16 2010/08/02 2011/06/18 2012/05/04 Protons per week (E18) 0 2 4 6 8 10 Total NuMI protons to 00:00 Friday 08 June 2012 Total Protons (E20) 0 2 4 6 8 10 12 14 16 Neutrino Running Antineutrino Running Special Running Antineutrinos Antineutrinos Antineutrinos MINOS ν μ and ν̄ μ Charged-Current Disappearance Analysis (hep-ex:1304.6335) The results presented are obtained using the complete MINOS beam data sample collected between 2005 and 2012. A total of 10.71x10 20 POT collected in neutrino mode and 3.36x10 20 POT collected in antineutrino-enhanced mode are used in the analysis. Muons from ν μ , ν̄̄ μ charged-current (CC) interactions are selected by multivariate algorithm based on a k-Nearest-Neighbor technique. The MINOS detectors are magnetized, enabling ν μ and ν̄̄ μ to be separated on an event-by-event basis, by analyzing the muon curvature. ν̄̄ μ CC events are identied by a positive muon charge sign. The neutrino energy is reconstructed by summing the muon momentum and hadronic shower energy. The plot on the right shows the energy spectrum in the Near Detector (ND) for selected ν μ CC events. The extrapolated ND spectrum is used to obtain the Far Detector unoscillated spectrum.
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Transcript of Charged-Current ̄µ ν MINOS Disappearance Analysis … · Combined Beam+Atmospherics...

  • Date2005/04/29 2006/03/15 2007/01/29 2007/12/15 2008/10/31 2009/09/16 2010/08/02 2011/06/18 2012/05/04

    Pro

    tons

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    Total NuMI protons to 00:00 Friday 08 June 2012

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    16Neutrino RunningAntineutrino RunningSpecial Running

    Antineutrinos

    Antineutrinos

    Antineutrinos

    MINOS and Charged-Current Disappearance Analysis (hep-ex:1304.6335)

    The results presented are obtained using the complete MINOS beam data sample collected between 2005 and 2012. A total of 10.71x1020 POT collected in neutrino mode and 3.36x1020 POT collected in antineutrino-enhanced mode are used in the analysis.

    Muons from , charged-current (CC) interactions are selected by multivariate algorithm based on a k-Nearest-Neighbor technique.

    The MINOS detectors are magnetized, enabling and to be separated on an event-by-event basis, by analyzing the muon curvature. CC events are identified by a positive muon charge sign.

    The neutrino energy is reconstructed by summing the muon momentum and hadronic shower energy. The plot on the right shows the energy spectrum in the Near Detector (ND) for selected CC events. The extrapolated ND spectrum is used to obtain the Far Detector unoscillated spectrum.

  • Charged-Current Disappearance Results

    For 0 < Ereco < 200 GeVPrediction, No Oscillations: 3564 eventsObserved: 2891 events

    Effect of Systematics

  • Charged-Current Disappearance Results

    For 0 < Ereco < 200 GeVPrediction, No Oscillations: 313 eventsObserved: 226 events

    Effect of Systematics

  • Combined Beam+AtmosphericsDisappearance Results

    Red histogram shows the result from fitting a two-neutrino flavor oscillation scenario to the combined beam and atmospheric neutrino and antineutrino data samples. Fit includes 15 sources of systematic uncertainty as nuisance parameters.

    Oscillations are a good fit: 19.1% of pseudo-experiments have worse 2.

  • Combined Beam+AtmosphericsDisappearance Results

    The MINOS beam and atmospheric neutrinos and antineutrinos are combined into a single oscillation analysis using an extended version of the fitting framework developed for the previous analysis.

    The analysis includes 15 sources of systematic uncertainty, fitted as nuisance parameters,

    A maximum-likelihood fit is used to determine the two-flavour oscillation parameters.

    An extension of the analysis from two to three-flavour oscillations is in progress

    Neutrinos+Antineutrinos

    m2

    = 2.41+0.090.10 103eV2

    sin2(2) = 0.950+0.0350.036

  • MINOS Allowed Regions Compared to Other Experiments

    MINOS makes the leading measurement of |m2atm| with 4.1% precision.

    MINOS Best Fit Parametersm2

    = 2.41+0.090.10 103eV2

    sin2(2) = 0.950+0.0350.036sin2(2) > 0.890 (90%C.L.)

  • Combined Beam+AtmosphericsDisappearance Results

    The MINOS oscillation fit is extended to allow different oscillation parameters for and .The extended fit is used to determine confidence limits on the antineutrino oscillation parameters by marginalizing over the neutrino oscillation parameters.

    sin2(2) = 0.97+0.030.08

    Plot above shows a comparison of MINOS antineutrino results for beam, atmospheric and beam+atmospheric samples with results from the Super-Kamiokande experiment

    Antineutrinos Only Antineutrinos Only

    m2

    = 2.50+0.230.25 103eV2

  • Neutrino vs. Antineutrino Disappearance

    MINOS finds consistent values for neutrinos and antineutrino oscillation parameters measured via charged-current disappearance.

    m2

    m2 = 0.12+0.240.26 103eV2