1. T2K: ND280 status, progress, and plans Steven Dytman, (Vittorio Paolone) University of Pittsburgh (Representing the T2K collaboration) NUFACT10 XII International Workshop on Neutrino Factories, Super beams and Beta beams 20 - 25 October 2010 TIFR, Mumbai, India

2. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh2 Outline Motivation: Oscillations Motivation: Oscillations T2K Experimental Overview ND280 Measurement Requirements T2K/ND280 Detector Elements T2K first physics run (Jan-June 2010): ND280 Performance Plans and Schedule

3. NuFact10: October 20-25, 2010 S. Dytman, University of Pittsburgh3 What is the Goal? 3-flavor mixing describes (almost) all neutrino oscillation phenomena (3 mixing angles, 2 independent mass splittings, 1 CPV phase) Interference: θ 13 and δ CP unknown θ 13 < 10 o (CHOOZ/MINOS) Atmospheric & accelerator: θ 23 ~ 45 o (Δm 23 ) 2 ~ 2.3x10 -3 eV 2 Solar & reactor: Θ 12 ~ 34 o (Δm 12 ) 2 ~ 8x10 -5 eV 2 Next generation experiments need to: Measure θ 13 and δ CP (if θ 13 ≠ 0) Mass hierarchy (Δm 2 23 > 0?) θ 23 maximal (45 o )?

4. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh4 T2K Overview Main objectives: Measure/improve limit on θ 13 (ν μ →ν e appearance) θ 13 ≠ 0 would allow to explore CPV in leptonic sector Improve measurement of Δm 2 23 and θ 23 ( ν μ →ν μ disappearance) Experiment Parameters : Long baseline (295 km) Very intense beam Massive far detector (SuperK) Near detector: ND280 (ν flux/ composition near source and measure background processes off of water) Off-axis design Enhance sensitivity at oscillation maximum Reduce intrinsic background SuperK – Water Cherenkov ND280 Location

5. NuFact10: October 20-25, 2010V. Paolone, University of Pittsburgh5 T2K Beam T2K is the first LBL ν experiment using an off-axis beam This configuration produces a narrow beam with peak energy (~600 MeV) tuned to first oscillation maximum (Δm 2 13 (=2.3 x 10 - 3 eV 2 ) L/4E ν ≈π/2 ) Reduces high energy tail: Reduces background (but does not eliminate) from non-QE interactions and NC feed down from high energy ν μ Beam direction is tunable, aimed 2.5 o off axis in the direction of Super-Kamiokande

6. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh6 JPARC Facility

7. NuFact10: October 20-25, 2010V. Paolone, University of Pittsburgh7 Neutrino Beam-line

8. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh8 ND280 Detector Suite Off-Axis Detector: In SK Direction, measure: flux Rates/Cross sections for water and plastic to reduce systematic errors on oscillation parameters

9. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh9 Expected Sensitivity Δm 2 23 =2.4x10 -3 eV 2, δ CP = 0 (δ CP can enhance or reduce the signal) e appearance: (sin 2 2θ 13 < 0.008 (90% C.L.)) With 5 x 0.75 MW x 10 7 s (8.3 x 10 21 PoT) μ disappearance: (δ(sin 2 2θ 23 )≈0.01 & δ(Δm 2 23 )<1x10 -4 eV 2 ) At full exposure, sensitivity depends on level of systematic errors

10. NuFact10: October 20-25, 2010V. Paolone, University of Pittsburgh10 T2K analysis strategy Measure ν μ flux at near detector Extrapolate flux from near to far detector using beam simulation; tuned/constrained by beam and hadron production data (NA61/Shine) Estimate ν μ rate (without oscillation) at far detector: N null Compare to measured ν e (ν μ ) rate (spectrum) to observe oscillation and extract oscillation parameters P(ν μ →ν μ ) ≈ 1− sin 2 2θ 23 sin 2 (Δm 2 23 L/4E ν ) Φ ND =N ND /(σ ND ε ND ) Φ FD =R(FD/ND)Φ ND N null =Φ FD σ FD ε FD P(osc)=N FD /N null Reconstructed v energy (GeV) MC ν e appearance sin 2 2θ 13 = 0.1 signal/BG ~ 7 (750kWx5x10 7 s) P(ν μ →ν e ) ≈ sin 2 2θ 13 sin 2 θ 23 sin 2 (Δm 2 13 L/4E ν ) ν μ disappearance N FD /N null

11. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh11 Background Processes ν μ background to CCQE ν μ measurements at Super-K is CCπ + ν μ/e + N → μ - /e - + N +  + Comparable size to CCQE ν μ background to ν e search at Super-K NC  0 : ν μ/e + N → ν μ/e + N +  0 Only π 0 →γγ detected in final state γ and e - are indistinguishable Intrinsic ν e in beam T2K Beam Critical to measure these processes at the near detector especially at full exposure using water targets

12. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh12 ND280: INGRID The INGRID is the On-axis detector and... : Consists of 16 modules of scintillator/iron sandwich planes Measures neutrino beam profile in X and Y Large mass allows quick feedback on beam shape.

13. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh13 ND280: Off-Axis … Is in UA1 Magnet: 0.2T B field Contained volume ~ 3.5m x 3.6m x 7m. SMRD (Side Muon Range Detector): Scintillator planes inserted into magnet yoke gaps. Detects large angle muons from inner detector. Provides cosmic ray trigger. ECAL: Scintillator planes with radiator. Measure EM showers from inner detector. Lines the inside of UA1 magnet and encloses inner detector. TRACKER: 2 FGDs (Fine Grained Detectors): scintillator planes: active target mass. 3 TPCs (Time Projection Chambers): Tracking, ID and momentum measurements of charged particles from FGD and P0D. P0D (  0 Detector): Scintillators planes interleaved with lead/brass/water; optimized for gamma detection. SMRD ECAL

14. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh14 ND280: P0D P0D consists of : 40 x-y scintillator planes (~10k scint. Bars) Middle: scint(8t)+H 2 O bags(3t) Front/back: calorimeter (veto and γ catcher) Pb+Scintillator (6.4t) Important background to Super-K e appearance (i.e. if SK misses one  from  0 ) is from Neutral-Current  0 :  + N   + N +  0 P0D optimized for measurement of gammas from  0  0 (Pi0) detector=P0D

15. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh15 ND280: SMRD ~2k scint. counters (87x17x0.7 cm3) Side Muon Range Detector: Sand muon veto, Cosmic trigger Large angle muon range Efficiency for MIP > 99%

16. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh16 ND280: ECAL Layers of scintillator bars (~21K) brass radiators: σ E /E~7.5%/√E Uses: Sand muon rejection Detect gammas for  0 analysis Detect bremsstrahlung in e measurement Schedule: Downstream ECAL in place for 1 st run Barrel ECAL installed during present shutdown

17. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh17 ND280: TPC Time Projection Chambers (TPC): Mechanical construction: double box design made from composite panels. Inner box with copper clad G10 skins, outer box with aluminum skins. Wireless readout with MicroMegas (7x10mm 2 pads) ~124k channels Excellent tracking and particle ID: 5σ e/μ separation, σ p /p < 10% at 1 GeV/c TPC inner box

18. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh18 ND280: FGD Fine Grained Detectors (FGD): X-Y scintillator planes (~8.4k scint. Bars) + H 2 O (in FGD2) FGD planes consist of long, thin scintillator bars Bars in planes alternate directions allowing for 3D tracking.

19. NuFact10: October 20-25, 2010S.Dytman, University of Pittsburgh19 ND280: Background Measurements Summary In summary to achieve the ultimate T2K sensitivity, we require accurate/precise measurements of background processes and unoscillated beam flux. This will be provided by 2 neutrino detectors at ND280- INGRID : On-axis – beam profile monitoring ND280 : Off-axis –  energy spectrum (flux x cross section) – Intrinsic beam e – NC  0

20. NuFact10: October 20-25, 2010S. Dytman, University of Pittsburgh20 ND280: Photosensers MPPCs Scintillator detectors read out via WLS fiber coupled to Si MPPC (667 pixel avalanche photodiode, area of 1.3x 1.3mm 2 ). Properties: Can isolate single PE's! High  eff, ~20-30% (green) gain similar to PMT’s Operating voltage ~70V. Hard to damage Insensitive to magnetic fields But.. High dark noise rates: ~0.5MHz. Cross-talk/afterpulsing. Properties (e.g. gain) depend strongly on temp and voltage. First large-scale use in HEP experiment: ~50,000 MPPCs for ND280 After First year of operation with MPPCs few- to-none have failed.

21. NuFact10: October 20-25, 2010S. Dytman, University of Pittsburgh21 Far Detector: SuperK IV 50 kton (22.5 kton fiducial) water Cherenkov det. ID: 11k 20'' PMT (40% photo coverage); OD: 2k 8'' veto PMT (optically isolated from ID) New readout electronics and DAQ (no dead time) – improved decay-electron tagging GPS based event timing – record events within 500 μs around spill Very efficient e/μ separation (~99% at 0.6 GeV)

22. NuFact10: October 20-25, 2010S. Dytman, University of Pittsburgh22 First Physics Run January 23 – June 26 2010 Beam power: ~50 kW stable running (trial shots up to 100 kW) Total data accumulated: 3.3x10 19 PoT

23. NuFact10: October 20-25, 2010S. Dytman, University of Pittsburgh23 INGRID Performance Typical event Event times: 6 bunches/spill Event rate (per 1x10 14 PoT) vs Time

24. NuFact10: October 20-25, 2010S. Dytman, University of Pittsburgh24 INGRID: Beam Profile Beam profile Beam center (from Gaussian fit) over run period (Required < +/- 1 mr variation over run full period)

25. NuFact10: October 20-25, 2010S. Dytman, University of Pittsburgh25 Off-Axis: Event Displays TPC1TPC 2 TPC 3 FGD1 FGD2DSECAL Live Channel Count: Excellent!

26. NuFact10: October 20-25, 2010S. Dytman, University of Pittsburgh26 Off-Axis: Performance P0D vertex distribution (x-y) TPC: dE/dx vs p Beam center FGD event timing FGD Neutrino Interaction Rate

27. NuFact10: October 20-25, 2010S. Dytman, University of Pittsburgh27 Short and Long Term Plans Summer/Fall shutdown tasks: New kicker magnets and power supplies: 6 → 8 bunch New horn power supplies: 250 kA → 320kA UK Barrel ECal installation completed Install 2 INGRID diagonal modules Resume data taking in November: Goal 150 kW x 10 7 s integrated power by July 2011 (~3.2 x 10 20 POT) Long term plans (2014): Reduce MR cycle: 3.5 to 2.23 s Increase LINAC energy: 181 to 400 MeV

28. Cross sections Near term: major need is understanding of relative rates for different topologies in water  NC  0 mimicking e -  e identification   production/absorption in target nucleus mimicking qe event  e content of beam significant work underway for tracking  0, charged particles. ND280 detectors are mixtures of water and plastic Systematic errors important after ~3 x 10 21 POT. Longer term: Many PhD theses will measure variety of cross sections in plastic and water  ~ few thousand events in larger channels (qe,  +,  0 res) in existing data, ~few hundred NC  0.  ~few x 10k events with data from next 2 years (~3.1 x 10 20 POT) absolute cross sections to ~20% with muon monitors, emulsion Improvements needed to get systematic error ~5%.

29. Cross section estimates Preliminary event rates: Events in P0D and FGD (plastic + water, no differentiation) Throw all interactions, apply simple cuts (T  >120 MeV(FGD), 160 MeV (P0D), T p >450 MeV (FGD), 550 MeV (P0D), E  >50 MeV Assume 10 21 POT (~next 3 years)  e Preliminary

30. NuFact10: October 20-25, 2010S. Dytman, University of Pittsburgh30 Summary T2K: High intensity off-axis long-baseline neutrino oscillation experiment designed to study  → e oscillations and more. ND280 needed to maximize physics reach and sensitivity New accelerator complex, beam line, and near detectors (ND280) were completed last year (week). First physics data taking concluded this year ND280 Detectors work! Running resumes after the Summer shutdown in mid-November. Stay tuned for first results...