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Long-Baseline Neutrino Oscillation Experiment

Long-Baseline Neutrino Oscillation Experiment. Robert J. Wilson for the T2K Collaboration 15 December 2010 NNN2010 – Toyama, Japan. . . . . . . . . Tokai. Super-Kamiokande. T2K Goals. Measure last unknown mixing angle θ 13 using ν μ ➞ ν e appearance

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Long-Baseline Neutrino Oscillation Experiment

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  1. Long-Baseline Neutrino Oscillation Experiment Robert J. Wilson for the T2K Collaboration 15 December 2010 NNN2010 – Toyama, Japan         Tokai Super-Kamiokande

  2. T2K Goals • Measure last unknown mixing angle θ13using νμ ➞ νe appearance • Precise measurement of the atmospheric parameters θ23 and Dm322 using νμ ➞ νμdisappearance R.J.Wilson/Colorado State University

  3. eAppearance in a Beam • Effectively 2-flavor mixing • Amplitude proportional to sin22q13 • No evident CP phase d dependence • L/E chosen for oscillation maxima T2K L = 295 km EnPmax 0.6 GeV Approximation to 3-flavor vacuum mixing with Dm212 << Dm322 R.J.Wilson/Colorado State University

  4. Neutrino Cross Sections • Charged-Current Quasi-Elastic (CCQE) dominant near 1st oscillation max • Good efficiency and energy resolution in Super-K • Major Backgrounds at Super-K • nm disappearance: CC p+ is comparable size to CCQE in nm measurement • ne appearance: NC p0, since g and e indistinguishable in Super-K • These factors guided the beam and near detector design R.J.Wilson/Colorado State University

  5. Neutrino Beam Flux n flux – 30 GeV p MR ON-AXIS • On-axis beam spectrum peaks ~2 GeV • Want to maximize neutrino flux at the appearance probability peak • Narrow spectrum to reduce backgrounds from higher energy processes R.J.Wilson/Colorado State University

  6. Off-Axis Beam Flux n flux – 30 GeV p MR ON-AXIS     • Correlation between neutrino energy and direction with pion energy • Optimum for 1st max flux and background reduction at ~2.5 off-axis R.J.Wilson/Colorado State University

  7. J-PARC  n p Off-axis detector Far Detector (SK) Target 2.5º m &Horns On-axis detector Decay pipe Muon monitor Near Detector 0m 120m 280m 295 km ND280 (INGRID) T2K Schematic • Beam monitoring • Primary beam monitors (intensity, position, profile) • Muon monitor after the decay pipe • On-axis detector (INGRID) at 280 m from the target • Beam characterization and cross section measurements • Near Detector at 280 m (ND280) 2.5° off-axis from the beam • Far detector neutrino flavor and flux measurement • Super-K 2.5° off-axis from the beam R.J.Wilson/Colorado State University

  8. Unoscillated flux at Super-K MC ~0.5% ne contamination at the peak • Almost pure nm beam • ne contamination ~1% R.J.Wilson/Colorado State University

  9. Oscillation Physics Sensitivity R.J.Wilson/Colorado State University

  10. dCP Dependence 3-flavor mixing in vacuum (matter effect is small for T2K baseline) • Effect of CP on the phase term is d-d hence the nomenclature dCP • Oscillation measurement, and measurement of sin22q13, depends on dCP • If any angle is zero oscillation measurement is not sensitive to dCP  measurement of q13 is critical for future CPV experiments J. Boehm R.J.Wilson/Colorado State University

  11. T2K θ13sensitivity (normal hierarchy) MINOS – Nu2010 m223 = 2.4 x 10-3 eV2 sin2 12 = 0.8704 m2 12 = 7.6 x 10-5 eV2sin2 23 = 1.0 Exposure: 750 kW X 5 X 107s X 22.5 ktfid. mass • sin2q13 sensitivity depends onunknown dCP; usually given for dCP =0

  12. Systematics: nm ne • Expected backgrounds at Super-K • Intrinsic ne in beam, ~60% • False e- candidates, e.g. from NC p0, ~40%  important to understand systematics on these backgrounds • Analysis goal is to keep fractional uncertainty on each background source to < 10% R.J.Wilson/Colorado State University 14

  13. νμ νeappearance sensitivity δCP= 0, Δm223 = 2.5 x 10-3 eV2 • Sensitivity goal : 0.006 (0.008) for normal (inverted) hierarchy (~1/20 CHOOZ limit) Effect ofsystematics Design Goal: 3.75 MW × 107s

  14. nmdisappearance Measured by Super-K Nobs m322 sin2223 ( ) R x NDx water sin22 = 1.0 m2 = 2.7 x 10–3 eV2 Far/Near Extrapolated from MC verified by NA61 Measured by near detectors Near detector flux

  15. Systematics: nm nm δ(sin22θ23) • EstimatedSystematics uncertainties • Normalization – 10% • Non-QE/QE ratio – 20% • Energy scale – 4% • Spectrum width – 10% δ(Δm223) R.J.Wilson/Colorado State University

  16. MINOS & Super-K preliminary @ Nu10 90% c.l. T2K w/ 3.75 MW×107 s Atmospheric parameters summary • Narrow beam spectrum centered on oscillation maximum •  good sensitivity to atmospheric parameters • Expected sensitivity • sin22θ23≈0.01 • Δm223 < 1.0 x 10-4 eV2 MINOS R.J.Wilson/Colorado State University

  17. T2K Beam & Near Detectors R.J.Wilson/Colorado State University

  18. 181 MeVLinac The JPARC Facility ND280 Pacific Ocean Neutrino Beamline (6 bunch Jan-June 2010) 30 GeV Proton Synchrotron 3 GeV RCS ~ 20 R.J.Wilson/Colorado State University Nakadaira-san talk for more details

  19. Accumulated Protons Summer Shutdown 68 bunches Rep. 3.6 3.2 sec • First T2K run (January to June 2010) • ~50 kW stable operation; 3.23 ×1019 protons for analysis • Second run started Nov. 16 – rapid ramp up to current 115 kW

  20. Neutrino Monitor Near Detector at 280 mND280 Off-Axis Detector Side Muon Range Detector 2.5 n beam On-Axis Monitor (INGRID) 0 Barrel ECAL installation finished Oct 2010 Completes ND280! R.J.Wilson/Colorado State University

  21. INGRID On-axis monitor First event Beam Profile X Beam Profile Center X • Monitor beam direction, intensity and mean energy • Off-axis angle measurement accuracy goal 1 mrad (< 15 MeV on off-axis peak energy) • Beam position resolution ~ 7 cm  ~3 mm shift at proton target • ~ 10k ν interactions per day at full power • Six bunch beam structure R.J.Wilson/Colorado State University

  22. ND280 off-axis neutrino events Event Rates (P0D+FGD)/1021PoT : 600k m- only 300k m-p 40k m-p0 8k e- only 5k e-p 0.8k e-p0 R.J.Wilson/Colorado State University

  23. Off-axis Detector Interaction Vertices P0D • Contained vertices reconstructed in P0D and FGD • Lines show (approximate) iso-contours of off-axis angle • Outer corner is roughly 20% further off-axis than inner corner 25 R.J.Wilson/Colorado State University

  24. Far Detector : Super Kamiokande IV • More details in Roger Wendell’s Talk • 50 kt (22.5 kt fid.) Water Cherenkov detector: 11,129 20” PMTS in inner detector (ID) and 1885 8” PMTS in outer detector (OD) • T2K • Dead-timeless read out electronics and DAQ upgrade in 2008 • GPS system used to select time arrival of beam events R.J.Wilson/Colorado State University

  25. Unbiased event selection • nm disappearance analysis ne appearance search • SK event selection decided before the run • Possible because SK is a mature & well understood detector

  26. T2K Events in Super-K pm = 1438 MeV/c 2 decay-electrons pm = 1061 MeV/c 1 decay-electron

  27. Super-K Time Distribution Low energy : NC g excitation Outer Detector Fully-contained Jan-June Nov.-Dec. • GPS works well - very good time synchronization between T2K beam and Super-K • Change 6->8 bunches since Nov. evident ∆T0 = SK trig time -T2K beam trigger time

  28. 2010/2011 Run • Started Nov. 18th • ~50% increase in data in 3 weeks • Current beam power ~115 kW • Aim for 150 kW × 107s by July 2011 • 10x 1st run data • sensitivity to sin22q13 0.05 July 2011 goal Design Goal: 3.75 MW × 107s R.J.Wilson/Colorado State University

  29. Summary • 1st run January–June 2010 • Continuous beam at ~50 kW, accumulated 3.23 x 1019 PoT • Good overall stability of beam and detector performance • Measured 23 neutrino beam events (FCFV) at Super-K • Expect first results by winter 2011 conferences • Summer/fall shutdown • New kicker magnet & power supplies installed • INGRID modules assembly and installation • Calorimeter modules installation completed - full coverage at ND280 • 2nd run November 2010 – Summer 2011 • Aim for 150 kW x 107 s by July 2011; currently > 110 kW • 90% c.l. sensitivity sin22q13 ~ 0.05 R.J.Wilson/Colorado State University

  30. Supplementary R.J.Wilson/Colorado State University

  31. T2K θ13 sensitivity (inverted hierarchy) • Similar to normal hierarchy • T2K insensitive to matter effects MINOS – Nu2010 R.J.Wilson/Colorado State University

  32. CERN NA-61/SHINE • Neutrino beam depends upon secondary beam geometry and hadron distribution off target • NA-61/SHINE : dedicated hadron production experiment using T2K target to reduce uncertainties in hadron production models • Pilot run in 2007 and high statistics run in 2009 : p(30 GeV) with Carbon thin target and T2K replica target • preliminary results from 2007 used in T2K beam MC MC=GFLUKA Preliminary

  33. T2K sensitivity and discovery potential 3s measurement R.J.Wilson/Colorado State University

  34. Beam Power Plan Japanese Fiscal Year (starts April 1 of CY) R.J.Wilson/Colorado State University

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