1 / 35

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

jace
Download Presentation

Long-Baseline Neutrino Oscillation Experiment

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related