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Appearance in MINOSUniversity of Minnesota

A.P. SchreckenbergerDPF 2011

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IntroductionA new MINOS analysis

Complementary to appearance studyFirst-time look at this oscillation mode by

MINOSCurrently under development – results in not

too distant future

Brief recap of apperanceMotivation for analysisDataset & sensitivity estimates

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Appearance in MINOS8.2e20 protons-on-target

analysis90% CL below the CHOOZ

limit with normal hierarchyΘ13 = 0 hypothesis

disfavored at 89% CL

Less sensitive to inverted mass hierarchy

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Why Greater sensitivity to inverted hierarchy

Δδ is CP-violating phase

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Why A, Δ and α flip signs in hierarchy changeA and δ flip signs under charge conjugation

Normal Hierarchy Inverted Hierarchy

What happens to the three terms?

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Why A, Δ and α flip signs in hierarchy changeA and δ flip signs under charge conjugation

Normal Hierarchy Inverted Hierarchy

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Why A, Δ and α flip signs in hierarchy changeA and δ flip signs under charge conjugation

Normal Hierarchy Inverted Hierarchy

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Why A, Δ and α flip signs in hierarchy changeA and δ flip signs under charge conjugation

Normal Hierarchy Inverted Hierarchy

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Why Appearance Probability as a function of energy

Generated using full probability expression

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Why Is there new physics to be seen?

Are there matter effects specific to ?Access to energies beyond the scope of reactor

experiments

Experimental motivationsMiniBooNE & LSNDMINOS: and observations

Consistent at 2.0% CL withidentical oscillation parameterhypothesis

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How do we get Horns focus off-axis particles of designated

chargePolarity determines which charge is focused

π−

π+

Target

Focusing Horns 2 m

675 m

νμνμ

15 m

30 m

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How do we get event rate suppressed due to decreased

cross-section

Neutrino Mode vs. Antineutrino Mode spectra

νμ: 58.1%͞�νμ: 39.9%͞�νe+νe : 2.0%

νμ: 91.7%͞�νμ: 7.0%͞�νe+νe : 1.3%

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Dataset

Neutrinos ~ 8.2e20 POTAntineutrinos ~ 3.0e20 POTSpecial Run Periods

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RHC Sensitivity Estimate for LEM

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Combining & AnalysesImprove limits on θ13 with joint analysisSimilarly sized POT additions have

constrained contours in the pastPursue whether combined analysis

will facilitate more significantdisfavoring of the θ13 = 0 hypothesis

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Summary & ConclusionSet limits on θ13 using an antineutrino beam

Estimated 3.5e20 POT exposureAccess to GeV energy scale neutrinos

Search for new physicsAnomalous matter effectsAntineutrino behavioral differences

Improve measurement of θ13 through a combined analysis

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Backup

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Appearance PIDsHave used two particle identification

algorithms (PIDs) in the past to select signal eventsANN11 – an artificial neural network

11 input variables generate a PID output for analysis use

LEM – Library Event Matching Matches topologies of candidate to library

consisting of simulated background and signal events

Also produces a PID for analysis use Offered increased sensitivity compared to ANN11