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T2K Experiment Results & Prospects

T2K Experiment Results & Prospects. Alfons Weber University of Oxford & STFC/RAL For the T2K Collaboration. Content. Neutrino Oscillations I ntroduction The T2K Experiment Beam Near Detector Far Detector Results Disappearance analysis Appearance search Future potential

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T2K Experiment Results & Prospects

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  1. T2K ExperimentResults & Prospects Alfons Weber University of Oxford & STFC/RAL For the T2K Collaboration

  2. Content • Neutrino Oscillations • Introduction • The T2K Experiment • Beam • Near Detector • Far Detector • Results • Disappearance analysis • Appearance search • Future potential • The hunt for CP-violation A.Weber, FLASY2014, Brighton

  3. Mass eigenstates m1, m2, m3 weak“flavour eigenstates” Unitary mixing matrix: 3 mixing angles & complex phases Neutrino MixingThe PMNS Matrix • Assume that neutrinos do have mass: • mass eigenstates  weak interaction eigenstates • Analogue to CKM-Matrix in quark sector! Pontecorvo-Maki-Nakagawa-Sakata A.Weber, FLASY2014, Brighton

  4. Oscillation Signatures eappearance: determine 13constrain dCP  disappearance: determine 23 and m232 Events Ratio of obs/expected Reconstructed ν Energy (MeV) Reconstructed ν Energy (MeV) Reconstructed ν Energy (MeV) A.Weber, FLASY2014, Brighton

  5. The T2K Experiment • A Long-baseline Experiment to study neutrino oscillations • Baseline 295 km • Beam power up to 230 kW • Detectors Near and far A.Weber, FLASY2014, Brighton

  6. Producing Neutrinos off-axis (2.5°) (30 GeV from MR synchrotron) π→μν 118 m Using NA61 data to constrain hadron production 0º A.Weber, FLASY2014, Brighton

  7. Data Taken • Data Set: 6.57 x 1020PoT (8% of design goal) • Increase power in future • More protons / bunch • Higher repetition rate A.Weber, FLASY2014, Brighton

  8. ND280 detector TPC1 TPC2 TPC3 νμ FGD2 FGD1 • Off-axis: ND280 • 0.2 T magnet (UA1/NOMAD) • Plastic scintillator detectors:Fine Grained Detector (FGD), π0detector (P0D), ECalsand SMRD,Time projection chambers (TPC) • On-axis: INGRID A.Weber, FLASY2014, Brighton

  9. Some ND distribution CC 1π+ CC 0π CC Other BEFORE FIT AFTER FIT • Select different event classes in near detector • Negative muon & something/nothing • Constrains flux and cross section uncertainties A.Weber, FLASY2014, Brighton

  10. Reduced Systematics A.Weber, FLASY2014, Brighton

  11. Far Detector A.Weber, FLASY2014, Brighton

  12. Far Detector Events A.Weber, FLASY2014, Brighton

  13. Electron Neutrino Appearance • Event Selection • Fully contained, • no π0 • No decay electrons A.Weber, FLASY2014, Brighton

  14. Appearance Result Phys. Rev. Lett. 112, 061802 (2014) A.Weber, FLASY2014, Brighton

  15. Compare with Reactors • Comparing with reactor measurements • best overlap is for the normal hierarchy δcp=–π/2. • Need to increase θ23to account for high event rate • Lucky point! Note: Marginalized over 23 and m232 A.Weber, FLASY2014, Brighton

  16. Disappearance Measurement Maximal mixing is not the same as maximumdisappearance if θ13is not zero! 120 selected events NH: sin2(θ23) = 0.514 NH: Δm232 = 2.51x10-3 eV2 A.Weber, FLASY2014, Brighton

  17. The World Scene A.Weber, FLASY2014, Brighton

  18. Putting it All Together A.Weber, FLASY2014, Brighton

  19. Run Status The width of the beam is comparable to the measured Gaussians in the previous runs. Measured with INGRID The detectors are all working well. Here is our first identified anti-neutrino event from an anti-neutrino test run! μ+ ND280 anti-ν event A.Weber, FLASY2014, Brighton

  20. Future Sensitivity “Lucky! (+: Sin22θ=0.1, δCP=-90)” NH 50% ν/50% anti-ν (true NH) 100% ν (true NH) T2K: 50% ν/50% anti-ν 100% ν (true NH) w/ Reactor constraint 50% ν/50% anti-ν (true NH) w/ Reactor constraint No systematics 5% error on signal, 10% on background T2K best sensitivity: 50% ν/50% anti-ν Anti-nu running: large new physics program. A.Weber, FLASY2014, Brighton

  21. Future Sensitivity (II) “Unlucky! (+: Sin22θ=0.1, δCP=0)” 50% ν/50% anti-ν (true NH) 100% ν (true NH) 50% ν/50% anti-ν (true NH) w/ Reactor constraint 100% ν (true NH) w/ Reactor constraint A.Weber, FLASY2014, Brighton

  22. T2K and NOvA T2K: 50% ν/50% anti-ν NH IH No systematics 5% error on signal, 10% on background A.Weber, FLASY2014, Brighton

  23. Summary and Conclusion • T2K has taken 8% of its nominal PoT • World leading results • 7.3σ electron neutrino appearance • Most precise measurement of θ23 • Combination with reactor measurements • Hint that δCP = -π/2 • Improved sensitivity with data to come • Can be lucky to “discover” CP violation • More results to come • Cross sections, sterile neutrinos, exotics… A.Weber, FLASY2014, Brighton

  24. Backup

  25. Who is Who νμ disappearance Solar neutrino oscillation ν–less double beta decay νedisappearance inνμbeam Or reactor neutrino experiments A.Weber, FLASY2014, Brighton

  26. Ubies? Open questions: Normal Hierarchy or Inverted Hierarchy? A.Weber, FLASY2014, Brighton

  27. NA61/SHINE ~13m ~10m • hadron(π, K) yield • 30 GeV p + C • High-acceptance • ToFsand spectrometers • 2cm thin target (4%λI) • π+ analysis: • dE/dx only analysis low momenta (Phys.Rev.C84.2011.034604) • dE/dx+ToFanalysishigh momenta(Phys.Rev.C85.2011.035210) A.Weber, FLASY2014, Brighton

  28. Predicted Flux νμ νe νμ • Primary pions modelled with NA61 data • νμ flux • Pions dominant at low energy • Kaons important in tail • νeflux • For low energy from muons A.Weber, FLASY2014, Brighton

  29. CC Interaction A.Weber, FLASY2014, Brighton

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