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Near detectors for long baseline neutrino experiments

Near detectors for long baseline neutrino experiments. T. Nakaya (Kyoto). T2K Near Detectors are operational and starts collecting n data. For the T2K collaboration. The detector is working inside of the UA/NOMAD magnet. Thanks to CERN. SciBooNE. MiniBooNE beamline. Decay region.

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Near detectors for long baseline neutrino experiments

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  1. Near detectors for long baseline neutrino experiments T. Nakaya (Kyoto) T. Nakaya

  2. T2K Near Detectors are operational and starts collecting n data. For the T2K collaboration The detector is working inside of the UA/NOMAD magnet. Thanks to CERN. T. Nakaya

  3. SciBooNE MiniBooNE beamline Decay region MiniBooNE Detector 440 m 100 m MINOS Far Detector Near detector T. Nakaya

  4. Functions of Near Detectors • Measure the neutrino flux times cross section for the normalization of the neutrino event rate at the far detector. • (Data/MC)#nm events = 0.8 ~ 1.8 ??? (10~20% error for sn and 10~20% error for hadron production) • Beam ne event rate for ne appearance search • Background estimation. • Monitor the neutrino beam itself for the long life of the neutrino experiment. • Running for ~5 years or longer. • Study the neutrino cross sections. • Low energy nuclear physics: not well understood nor not well modeled. • Play ground of the new technologies for experimentalists. • MPPC, TPC w/ Micromegas in T2K, etc.. Challenge new ideas, new designs, etc.. T. Nakaya

  5. Measurement of the n event rate Far detector Near detector Intense beam n, n, n, n p, p, p, p, K protons oscillation Fn(E) s s Hadron Production Near: Far: R(En): Far/Near Flux ratio  beam MC, hadron production P(En): Neutrino Oscillation Probability

  6. Monitor the neutrino beamK2K (1999~2004) n event rate (1KT) n beam direction (MRD) m energy in n interactions(MRD) T. Nakaya

  7. Study of ncross sections- K2K SciBar events - 3track event CC-1p (m+p+p) candidate CCQE candidate (n+nm+p) NC p0 candidate n+Nn+N+p0 1.3x2.5 cm2 segmentation size ne CCQE candidate

  8. Recent SciBooNE resulton NC coherent p0 production mp0 w/ VA (> 2MeV) w/o VA (< 2MeV) Vertex Activity (VA) T. Nakaya

  9. (5.8 s significance) Puzzle T. Nakaya

  10. New technology in T2K-ND280 HAMAMATSU MPPC Big TPC w/ MicroMegas 1.3mm 1.3mm 2 1 3 # photons 4 0 5 6 T2K-ND280OA 7 8

  11. TN personal view T2K/JPARC ne appearance 2010~2015 NO Future YES Big CPV & suppress ne app. 2015~ • Anti-n measurement NO YES 2020~ Tiny q13 • Build a gigantic n detector. • n and anti-n • two nosci. peak New Idea T. Nakaya

  12. v water C Liq. Ar Study Symmetry Violation between n and n T2K Beyond J-PARC Power Upgrade KEK Roadmap →1.66MW • Gigantic n detector • Water Cherenkov • Liquid Ar. TPC • O(~100k)ton GUT Proton Decay

  13. Hyper-K @ Kamioka v water C # CP sensitivity sin22q13 295km d Discovery potential of ＣＰV phase din 20°～160°、200°～340°

  14. 100 ktLq. Ar νeSpectrum sin22θ13=0.03,Normal Hierarchy • @ 658km • n beam only δ=0° δ=90° δ=180° δ=270° CP Measurement Potential d Okinoshima Beam νe Background 3s 658km 0.8deg. Off-axis sin22q13 NP08, arXiv:0804.2111

  15. K. Kaneyuki @ NP08 expected event rate @ Mton Water Cherenkov detector expected events w/o n oscillation expected events with n oscillation nmbeam nmbeam nm CC nm CC events/Mton/1MW/yr/50MeV nm NC beam ne nm NC nmbeam nmbeam En(GeV) En(GeV) nm CC nm CC nm NC nm CC nm NC nm NC nm CC En(GeV) En(GeV) beam ne beam ne nm and ne in nm beam should be carefully considered.

  16. reconstructed En distribution nm beam nm beam ne signal ne signal nm NC nm NC nm NC Enrec ne beam ne beam ne beam Enrec Enrec nmbeam : 1.66MW 2.2yr Enrec after all cuts nmbeam : 1.66MW 7.8yr sin22q13=0.1 Enrec Enrec

  17. Why a near detector? • Water Cherenkov • Better understanding of the anti-n beam. • Improve the knowledge of neutrino interactions, especially for anti-n. • Liq. Ar. TPC • Resolution of the neutrino energy reconstruction including the effect of the feed-down from the high energy part. • Detector Performance • Neutrino Interactions Study and demonstrate the above physics&effects in the near detectors. T. Nakaya

  18. How much segmentation is desirable?in the case of SciBooNE for CC-QE SciBooNE (Internal) • SciBooNE • n beam ~ 1GeV • 2D view × 2 • Segmentation: 2.5×1.3 cm2 (effectively 2.5 × 1.3 ) • Note: T2K-FGD 1×1 cm2 (effectively 1× 2 ) ignore ignore cm MeV/c T. Nakaya

  19. How much segmentation is desirable?in the case of SciBooNE for CC-QE • SciBooNE (~10 cm tracking capability) • n beam ~ 1GeV • 2D view × 2 • Segmentation: 2.5×1.3 cm2 (effectively 2.5 × 2.6 ) • Note: T2K-FGD 1×1 cm2 (effectively 1× 2 ) • Aim • a few mm segmentation • ~1cm tracking and patter recognition capability • (3D view) #tracks T. Nakaya

  20. Electron calorimeter T. Nakaya August 25, 2004 @ T2K meeting Conceptual Off-Axis 280m Detector in 2004 Magnet (and side MRD) Magnet (and side MRD) Tracker (TPC or chambers) Fine Grained detector w/ or w/o water target Iron shield for m-ID Scintillator Realization/Operation in 2010

  21. One vague idea of TN Electron calorimeter A Conceptual Design of the T2K-ND280m Detector Upgrade(no relation to the T2K collaboration) Magnet (and side MRD) Magnet (and side MRD) Gas TPC Fine Grained detector Lq. Ar TPC Scintillating fiber camera (1~2mm fiber) FGD w/ water scintillator Idea (2010?) ➝ Realization/Operation 2016?~

  22. BACKUP T. Nakaya

  23. T. Nakaya

  24. T. Nakaya

  25. Water Cherenkov T. Nakaya

  26. Better with antineutrinos How correct they are?

  27. number of events on each step (nm beam 1.66MW 2.2yr sin22q13=0.1)

  28. number of events on each step (nm beam 1.66MW 7.8yr sin22q13=0.1)

  29. reconstructed En distribution (sin22q13=0.1) d=0 d=p/2 signal+BG nm+nm+ne+ne BG nm nm+nmBG Enrec Enrec nm Enrec Enrec

  30. reconstructed En distribution (sin22q13=0.03) d=0 d=p/2 signal+BG nm+nm+ne+ne BG nm nm+nmBG Enrec Enrec nm Enrec Enrec

  31. uncertainty for ne (ne) signal reconstructed En distribution • Uncertainty • nmflux • nm flux • s(nm)→s(ne) • s(nm)→s(ne) • non-QE/QE • Far/near • efficiency • energy scale K2K d(Nint1kt)=4.1% d(nonQE/QE)=~6% d(NC/CC)=5% d(F/N)=3% d(E scale)=~2% d(eff)=~5% nm beam QE+nonQE nonQE ND NA61 nm beam FD cancelation between nm and nm beam is expected

  32. background from nm and nm mis PID mis PID orp0 D→gN mis PID p0 D→gN p0

  33. Lq. Ar. T. Nakaya

  34. Spectra for ne CC events 45 25 0 deg 90 deg • Shaded is beam ne background, while histogram shows the osc’d signal. • dcp effects are seen in 1st and 2nd osc. Maxima. (perfect resolution case) 0 4 0 4 60 270 deg 40 180 deg NP08 (@Mito) on Mar-6-2008 0 4 0 4

  35. Number of CC events • No oscillation case • ne appearance signal at various dcp NP08 (@Mito) on Mar-6-2008

  36. Fitter to extract the parameters Example of Fit (1 Pseudo-data) • The spectrum is fit by varying free parameters. (dCP and q13) • Fit is based on Poisson probability of bin by bin. (binned likelihood) • right plot • True dCP=0, sin2q13=0.03 • Best fit dCP=-0.5, sin2q13=0.031 Best fit data Number of events (50MeV bin) Perfect resol. NP08 (@Mito) on Mar-6-2008 Neutrino Energy (GeV)

  37. Allowed regions Perfect resolution case • This is perfect energy spectrum case • Cases at dcp=0,90,180,270 and sin22q13=0.1,0.05,0.03 are overlaid. • Each point has 67,95,99.7% C.L contours NP08 (@Mito) on Mar-6-2008

  38. Importance of Resolution (1) • “Resolution” includes; • neutrino interaction • Fermi motion • Nuclear interaction for final state particles. • Vertex nuclear activities (e.g. nuclear break up signal) • NC p0 event shape including vertex activity • detector medium • Ionization • Scintillation • Charge/light correlation • Signal quenching (amount of ionization charge/scinti. light is non-linear to dE/dx. E.g.including recombination ) • hadron transport • Signal diffusion and attenuation • readout system including electronics • Signal and Noise Ratio • Signal amplification • Signal shaping • reconstruction • Pattern recognition • p0 event shape • Particle ID We assume these effects causes Gaussian resolution, then see the results NP08 (@Mito) on Mar-6-2008

  39. Importance of Resolution(2) perfect • Assuming constant Gaussian resolution • independent on energy • Looks resolution is crucial (100MeV at most) 40 20 0 deg 90 deg 200MeV 5 0 0 5 40 60 270 deg 180 deg 100MeV NP08 (@Mito) on Mar-6-2008 0 5 0 5

  40. Importance of Resolution • 200MeV resolution can still make some • results, however, 100MeV is really preferable • to see the 2nd oscillation maximum visually. • “”robustness of the result” perfect 200MeV 100MeV NP08 (@Mito) on Mar-6-2008

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