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Appearance in MINOS

Appearance in MINOS. University of Minnesota A.P. Schreckenberger DPF 2011. Introduction. A new MINOS analysis Complementary to appearance study First-time look at this oscillation mode by MINOS Currently under development – results in not too distant future Brief recap of apperance

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Appearance in MINOS

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  1. Appearance in MINOS University of Minnesota A.P. Schreckenberger DPF 2011

  2. Introduction • A new MINOS analysis • Complementary to appearance study • First-time look at this oscillation mode by MINOS • Currently under development – results in not too distant future • Brief recap of apperance • Motivation for analysis • Dataset & sensitivity estimates

  3. Appearance in MINOS • 8.2e20 protons-on-target analysis • 90% CL below the CHOOZ limit with normal hierarchy • Θ13 = 0 hypothesis disfavored at 89% CL • Less sensitive to inverted mass hierarchy

  4. Why • Greater sensitivity to inverted hierarchy • Δ • δ is CP-violating phase

  5. Why • A, Δ and α flip signs in hierarchy change • A and δ flip signs under charge conjugation Normal Hierarchy Inverted Hierarchy What happens to the three terms?

  6. Why • A, Δ and α flip signs in hierarchy change • A and δ flip signs under charge conjugation Normal Hierarchy Inverted Hierarchy

  7. Why • A, Δ and α flip signs in hierarchy change • A and δ flip signs under charge conjugation Normal Hierarchy Inverted Hierarchy

  8. Why • A, Δ and α flip signs in hierarchy change • A and δ flip signs under charge conjugation Normal Hierarchy Inverted Hierarchy

  9. Why • Appearance Probability as a function of energy • Generated using full probability expression

  10. Why • Is there new physics to be seen? • Are there matter effects specific to ? • Access to energies beyond the scope of reactor experiments • Experimental motivations • MiniBooNE & LSND • MINOS: and observations • Consistent at 2.0% CL withidentical oscillation parameterhypothesis

  11. How do we get • Horns focus off-axis particles of designated charge • Polarity determines which charge is focused Focusing Horns Target 2 m π− νμ νμ π+ 30 m 15 m 675 m

  12. 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%

  13. Dataset Neutrinos ~ 8.2e20 POT Antineutrinos ~ 3.0e20 POT Special Run Periods

  14. RHC Sensitivity Estimate for LEM

  15. Combining & Analyses • Improve limits on θ13 with joint analysis • Similarly sized POT additions have constrained contours in the past • Pursue whether combined analysiswill facilitate more significantdisfavoring of the θ13 = 0 hypothesis

  16. Summary & Conclusion • Set limits on θ13 using an antineutrino beam • Estimated 3.5e20 POT exposure • Access to GeV energy scale neutrinos • Search for new physics • Anomalous matter effects • Antineutrino behavioral differences • Improve measurement of θ13 through a combined analysis

  17. Backup

  18. Appearance PIDs • Have used two particle identification algorithms (PIDs) in the past to select signal events • ANN11 – 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

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