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Super muon-neutrino beam

n Fact02 July 1, 2002 Imperial College London. Super muon-neutrino beam. Takashi Kobayashi IPNS, KEK. Contents Introduction “Super-beam” long baseline experiments Physics sensitivity Summary. Next goals of LBL experiments. Establish 3 flavor framework (or find something new)

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Super muon-neutrino beam

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  1. nFact02 July 1, 2002 Imperial College London Super muon-neutrino beam Takashi Kobayashi IPNS, KEK • Contents • Introduction • “Super-beam” long baseline experiments • Physics sensitivity • Summary

  2. Next goals of LBL experiments • Establish 3 flavor framework (or find something new) • Discovery of ne appearance (q13>0?) • At the same Dm2 as nm disapp. Firm evidence of 3gen. mix. • Open possibility to search for CPV • Confirmation of nmnt • Appearance • NC measurement • Precision measurements of ocs. params. • Dm23,q23/Dm13,q13 • Test exotic models (decay, extra dimensions,….) • Sign of Dm2 • Search for CPV in lepton sector • Give hint on Matter/Anti-matter asymmetry in the universe

  3. Decay Pipe Focusing Devices Proton Beam Target m nm p,K Beam Dump • Pure nm beam (≳99%) • ne (≲1%) from pme chain and K decay(Ke3) • nm/nm can be switched by flipping polarity of focusing device What’s super muon-neutrino beam? “Conventional” neutrino beam production with MW-class proton beam For high precision LBL experiments

  4. “Super beam LBL experiments”≈ “2nd generation LBL experiments w/ high intensity conventional beam” • High statistics • Beam intensity ≲100kW  ≳MW (super beam) • AND/OR detector mass ~10kt  100~1,000kt • Designed and optimized after the knowledge of Super-Kamiokande/K2K results • Primary goal: ne app.  CPV, sign of Dm2 • Japan: JHF(off-axis)SK/HK • FNAL: Off-axis NuMI, Proton driver upgrade, • BNL: Super AGS(off-axis)? • CERN: SPLFurejus, Off-axis CNGS

  5. p0 nx g nx nx p p p Next critical pathnmne appearance Backgroud Signal • Beam intrinsic ne contamination • Identical signature w/ signal • Different energy distribution • NC p0 production • NC multi pion production nm ne Single EM shower

  6. Key for ne appearance experiment • High statistics • Small background contamination (beam) • intrinsic ne short decay pipe,… • off-axis, … less high energy tail  less inelastic • Background rejection (beam+detector) • event topology (e⇔p0) • narrow spectrum beam w/ neutrino energy reconstruction  additional kinematical constraint • Small systematic error on background estimation • near/far spectrum difference • cross section • detector response

  7. Far Det. q Decay Pipe Horns Target En(GeV) En(GeV) Ep(GeV) High intensity narrow band beam-- Off-axis (OA) beam -- (ref.: BNL-E889 Proposal) nm flux Decay Kinematics 1 2 5 1/gp~q • Increase statistics @ osc. max. • Decrease background from HE tail

  8. Charged current cross sections • Inelastic • NCp0 • multi p • …. CCqe dominate ≲1GeV Inelastic dominate ≳1GeV Backgroud CCqe (nm+nm+p)

  9. Background rejection Typical OA spectrum • Event topology • p0: for example, • additional EM activity? • vertex displacement (g flight) • angular distribution • intrinsic beam ne: no way • En distribution • Signal peaked at osc. max. • Fake “ne” event by p0&beam ne broad OA2deg@JHF nm ne

  10. En reconstruction • ≲1GeV • 2-body kinematics of dominant CCqe • Water Ch. works well • ≳1GeV • Inelastics (nuclear resonances) dominate • (Fine grain) sampling calorimeter. Resolution? • Full reconstruction of secondary particles?

  11. m- m- nm+ n→ m+ p+ p nm+n→m + p (Em, pm) (Em, pm) ql qm n n p p inelastic CCqe En reconstruction ≲1GeV region  CC quasi elastic reaction p CCqe Inelastic (BG) SK Full Det. Sim. s~80MeV(10%) limited by Femi motion Small BG

  12. Typical OA beam(80mDV) 295km 280m Syst. error: far/near spectrum diff. K2K case (MC) FD(300m) (xLSK2/LFD2) SK Large(~x2) effect around peak!! Important not only for nm disappearance, but also for sig/BG estimation for ne search

  13. (“super-beam”) LBL experiments • The plans are in very different phases. Most are in optimization phase. • JHF-SK most advanced • budget request submitted • EXISITING real detector

  14. JHF-Kamioka Neutrino Project (hep-ex/0106019) Plan to start in 2007 Kamioka ~1GeV n beam JAERI (Tokaimura) Super-K: 22.5 kt Hyper-K: 1000 kt 0.77MW 50 GeV PS 4MW 50 GeV PS ( conventional n beam) Phase-I (0.77MW + Super-Kamiokande) Phase-II (4MW+Hyper-K) ~ Phase-I 200

  15. Principle of JHF-Kamioka project • Intense Narrow Band Beam by “off-axis”. • Beam energy is at the oscillation maximum. • High sensitivity, less background • ~1 GeV n beam for Quasi-elastic interaction. m events En(reconstruct) s=80MeV En (True) En(reconstruct) – En (True) (MeV)

  16. JHF Facility Super Conducting magnet for n beam line JAERI@Tokai-mura (60km N.E. of KEK) (0.77MW) Construction 2001～2006 (approved) Near n detectors @280m and @~2km Budget Request of the n beam line submitted 1021POT(130day)≡ “1 year”

  17. Osc. Prob.=sin2(1.27Dm2L/En) Dm2=3x10-3eV2 L=295km nm osc.max. OA1° OA2° OA3° Expected spectrum ne contamination 0.21% m-decay K-decay Very small ne/nm @ nm peak ~4500 tot int/22.5kt/yr ~3000 CC int/22.5kt/yr

  18. Detectors at near site • Muon monitors @ ~140m • Behind the beam dump • Fast (spill-by-spill) monitoring of beam direction/intensity • First Front detector“Neutrino monitor” @280m • Intensity/direction • Neutrino interactions • Second Front Detector @ ~2km • Almost same En spectrum as for SK • Absolute neutrino spectrum • Precise estimation of background • Investigating possible sites Neutrino spectra at diff. dist 1.5km 295km 280m 0.28km

  19. Far Detectors 1st Phase (2007~, ≥5yrs) Super-Kamiokande(22.5kt) 2nd Phase (201x~?) Hyper-Kamiokande(~1Mt) ４１．４ｍ ４０ｍ 48m × 50m ×500m, Total mass = 1 Mton

  20. USA: FNAL and BNL plan • BNL: Super AGS (1.3MW, LOI submitted) • FNAL: Super NUMI (1.6 MW) or the new proton driver. (hep-ex/0205040,0204037,hep-ph/0204208) Soudan Off-axis beams + 2 detectors Homestake WIPP 100km FNAL BNL

  21. OA-NuMI A. Para, M. Szleper, hep-ex/0110032 Osc. max. @ 730km 1.8GeV (Dm2=3x10-3eV2) Features • Nuclear resonance region  Inelastic background  Energy reconstruction? • Too large angle Kaon peak • Beam goes 3.5deg downward  hard to place 2nd near det.  Far/near ratio? Para/Szleper’s prescription using Matrix (hep-ex/0110001) K decay 0.78deg

  22. Europe: SPLFurejus CERN Geneve • SPL @ CERN • 2.2GeV, 50Hz, 2.3x1014p/pulse • 4MW Now under R&D phase 130km 40kt 400kt Italy

  23. Detectors Liquid Ar TPC (~100kton) UNO (400kton Water Cherenkov)

  24. Physics Sensitivity

  25. m e p0 ne appearance in JHF-Kamioka (phase 1) Backgrounds 9.3 events 1.8 events 11.1 events Signal 123.2 events @ sin22q13=0.1, Dm2=3×10-3eV2 (5 years running)

  26. ne appearance (continue) sin22qme=0.05 (sin22qme 0.5sin22q13) Dm2 CHOOZ ×20 improvement 3×10-3 sin22qme =1/2sin22q13 sin22q13<0.006 (90% C.L.)

  27. (log) Dm2=3×10-3 sin22q=1.0 sin22q ~3% Dm2 nm disappearance 1ring FC m-like dsin22q Oscillation with Dm2=3×10-3 sin22q=1.0 d(sin22q) OAB-2degree Non-QE 0.01 310-3 True Dm2 Reconstructed En (MeV) dsin22q23 ~ 0.01 dDm232< 1×10-4eV2

  28. 4MW,1Mt 2yr for nm 6.8yr for nm Sensitivity(3s) to CPV(2nd phase) Chooz excluded @Dm31~3x10-3eV2 d>~14deg d>~27deg Preliminary JHF1 3s discovery

  29. CHOOZ US Super n beam • They are studying the physics potential of several options, which are competitive to JHF-Kamioka project. NUMI-offaxis 0.003 |Ue3|2 =1/4sin22q13

  30. (Dm2)sol=10-7eV2 sin2qsol=0.25 sin2qatm=0.5 Possibility to discriminate sign of Dm2 (Matter effect) hep-ex/0206025 • Small matter effect in JHF-SK (~1GeV-295km) • Other longer baseline projects could play complementary role OA-NuMI MC study Dm232true=+ Running time nm:nm~1:3 (cross sec. diff) 3s For example, ~5yrs of OA-NuMIx20kt(w/ proton driver)

  31. Summary • Exciting topics in 2nd generation LBL experiments. • ne appearance • CPV, sign of Dm2, …… • Several “super-beam” experiments are under consideration • US, Europe and Japan • They are in very different stages. • Earliest beam is expected in 2007 at JHF-Kamioka project • Accelerator construction started in 2001. • Budget request for n facility submitted this year.

  32. Summary (II) • Physics sensitivity of JHF-Kamioka project • sin2q13≤0.006 (90%CL) • d(Dm2)≲3%, d(sin2q23)~1% • can discover CPV if d≳20o (in 2nd phase) • Experiments are complementary each other • JHF-Kamioka hard to see matter effect •  Longer baseline/higher energy experiments • nFact will come after the (at least) 1st round of super-beam experiments (10~20yrs) • If sin2q13≲0.01, JHF-SK may not see, but JHF-HK may. • But sensitivity to CPV in JHF-HK reduces •  CPV in nFact?

  33. sin22q13>0.018? Future Prospect 2002 : JHFn budget request&approval 2003 : start construction 2005 : K2K final results 2007 JHF1 Hint? 201x 3s discovery JHF2 Search q13 <10-3 Proton decay JHF2 CPV precision meas. q13 Proton decay 20xx Future SuperBeam, VLBL, n-fact for very small q13, CPV, sign of Dm2

  34. (Super) Neutrino Beams

  35. FNAL, BNL to Soudan • Water Cherenkov like Super-K 1 off-axis Events/0.1GeV/5years/100kTon Events/0.1GeV/5years/10kTon x

  36. 3. Experiments with the super neutrino beam

  37. Contents • Introduction • Physics goals of next generation long baseline experiments • Super-beam experiments • Physics potential of super-beam experiments • Comparison with nFact • Open questions • Summary

  38. Far/near spectrum ratio 0.5km Decay pipe len. LDV=80m 0.28km want near det. @ ≳10xLDV 1.0km 1.5km 2.0km 0 1 3 5 (GeV)

  39. Sensitivity for Mixing Angle sin22qme sensitivity ~JHF2-HK 1yr

  40. nm →nt confirmation w/ NC interaction • NC p0 interaction(n + N →n + N + p0) • nmne CC + NC(~0.5CC) ~0 (sin22qme~0) nm CC + NC(~0.5CC) ~0 (maximum oscillation)nt NC #p0 is sensitive to nt flux.Limit on ns (df(ns)~0.1) nmnt CC nt t #p0 + #e-like D=390±44 nt NC nt nmns p0 3.510-3 Dm232

  41. (High Intensity) Proton Accelerators Not the construcion stage yet, but R&D stage.

  42. Some ideas for OA-NuMI detector(under consideration) SOMINOS(Fe+Sci) Szleper+Velasco Plastic pellets +RPC (A.Para) 20m 20m 5kt, 12m dia., 875planes 1m 70ton/plane

  43. Super Proton Linac (SPL) @ CERN Reuse some parts from LEP Under R&D phase

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