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Super Beam Experiments

Super Beam Experiments. What’s a Super Beam? The Physics Some of the common features Specific Proposals Jaeri to Super-Kamiokande CERN to Frejus CERN to Gulf of Taranto Fermilab to “Up North” via NuMI Brookhaven to NUSEL (or others?) Conclusions. Douglas Michael

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Super Beam Experiments

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  1. Super Beam Experiments • What’s a Super Beam? • The Physics • Some of the common features • Specific Proposals • Jaeri to Super-Kamiokande • CERN to Frejus • CERN to Gulf of Taranto • Fermilab to “Up North” via NuMI • Brookhaven to NUSEL (or others?) • Conclusions Douglas Michael California Institute of Technology NuFACT 03 June 5, 2003

  2. Thanks • Thanks to the following people from whom I have borrowed/collected various slides and figures which I have included in this talk: • J. Cooper, M. Diwan, F. Dydak, A. Kondo-Ichikawa, K. McDonald, M. Mezzetto, T. Nakaya, K. Nishikawa, A. Para, S. Wojcicki • Those are my sources… I appologize if they have borrowed from you and I haven’t followed the chain of acknowledgement.

  3. What’s a “Super Beam” Experiment? • I know it when I see it. (Justice Potter Stewart) • Any conventional neutrino beam experiment where currently there is: • No Accelerator or • No Detector or • No Beamline or • Combinations of all of the above. • A conventional neutrino beam experiment with a whole lot of proton power and a really big detector. • I’ll settle for defining a “Super Beam” experiment as any conventional, long baseline, high energy neutrino beam experiment seriously “proposed” but not yet approved.

  4. Physics Goals • Improved measurement of nm disappearance oscillation parameters. • Any odd energy/distance features? • How close is sin22q23 to 1.0? New symmetry? • Measure the m23 mass heirarchy using matter effects. • Measure q13 or show that it is so small that it is somehow “odd” compared to the other mixing parameters… Mechanism for making it so small? • Attempt to measure CP violation, if q13 is big enough. • Constrain CPT violation (or discover it!) • And what if LSND is confirmed???????? Things get very interesting, and complicated.

  5. nm ne oscillation experiment 3 unknowns,2 parameters under control L, E, neutrino/antineutrinoNeed several independent measurements to learn about underlying physics Note, if there are any sterilen’s things can be more complicated!

  6. Anatomy of Bi-probability ellipses Minakata and Nunokawa, hep-ph/0108085 ~cosd • Observables are: • P • P • Interpretation in terms of sin22q13, d and sign of Dm223 depends on the value of these parameters and on the conditions of the experiment: L and E d ~sind sin22q13 Example from NuMI Off-Axis

  7. Oscillation probability vs physics parameters Parameter correlation: even very precise determination of Pn leads to a large allowed range of sin22q23  antineutrino beam is more important than improved statistics Example from NuMI Off-Axis

  8. The Off-Axis Trick At this angle, 15 mrad, energy of produced neutrinos is 1.5-2 GeV for all pion energies  very intense, narrow band beam ‘On axis’: En=0.43Ep

  9. Jaeri-Kamioka Neutrino Experiment (hep-ex/0106019) 2008? Plan to start in 2007 Kamioka ~1GeV n beam Super-K: 22.5 kt J-PARC (Tokai) Hyper-K: 1000 kt 0.75MW 50 GeV PS 4MW 50 GeV PS ( conventional n beam) JHF 0.75MW + Super-Kamiokande Future Super-JHF 4MW + Hyper-K(~1Mt) ~ JHF+SK 200 Kondo-Ichikawa

  10. J-Parc Facility Construction 2001～2006 (approved) nbeam-line budget request submitted (0.75MW) To SK Kondo-Ichikawa Near detectors (280m,2km)

  11. Super-K. q Decay Pipe Target Horns Off Axis Beam (ref.: BNL-E889 Proposal) • Quasi Monochromatic Beam • x2~3 intense than NBB Tuned at oscillation maximum ~0.7 GeV Statistics at SK (OAB2deg,1yr,22.5kt) ~4500nmtot ~3000nmCC ne~0.2% atnmpeak OA1° OA2° OA3° ~102 x (K2K) Kondo-Ichikawa

  12. Top view Side View Decay Volume 4MW beam can be accepted. Kondo-Ichikawa

  13. Neutrino spectra at diff. dist 1.5km 295km 0.28km Detectors p p n 0m 140m 280m 2 km 295 km • Muon monitors @ ~140m • Fast (spill-by-spill) monitoring of beam direction/intensity • First Near detector@280m • Neutrino intensity/spectrum/direction • Second Near Detector @ ~2km • Almost same En spectrum as for SK • Water Cherenkov can work • Far detector @ 295km • Super-Kamiokande (50kt) dominant syst. in K2K Kondo-Ichikawa

  14. sin22q MINOS 7.4 MINOS 25 MINOS 7.4 MINOS 25 Measurement of sin2 2θ23 , Dm223 Based on 5 years running with full 0.75 MW Jaeri Beam nm disappearance FC, 1-ring, m-like events Sys. error 10% for near/far 4% energy scale 20% non-QE B.G. d(sin22q23) OAB-3o OAB-2o d(Dm232 ) MeV Dm2 True Dm232 (eV2) d(sin22q)~0.01 d(Dm2) ~<1×10-4 Kondo-Ichikawa

  15. m e p0 ne appearance in JHF-Kamioka • Back ground for ne appearance search • Intrinsic ne component in initial beam • Merged p0 ring from nm interactions Requirement 10% uncertainty for BG estimation The 1kt p0 data will be studied for exercise Kondo-Ichikawa

  16. sin22q13 from ne appearance at Off axis 2 deg, 5 years CHOOZ excluded Dm2 Off axis 2 deg, 5 years Sin22q13>0.006 sin22q13 Kondo-Ichikawa

  17. 3. JHF n experiment -CPV 295km <En>~0.7GeV Kamioka Tokaimura n 4MW 50GeV Protons 0.54Mton Kamiokande Nakaya

  18. OAB (2degree) nm 0.21% m-decay ne K-decay n / n beam flux nm ~15% diff. nm (flip horn polarity) Nakaya

  19. Hyper-Kamiokande Possible site for Hyper-K SK ~10km HK ~540kton fiducial volume Nakaya

  20. Expected signal and Background nm:2yr, nm:6.8yr 4MW 0.54Mt Dm212=6.9x10-5eV2 Dm322=2.8x10-3eV2 q12=0.594 q23=p/4 q13=0.05 (sin22q13=0.01) Nakaya

  21. number of ne,ne appearance events sin22q13=0.01 # of e+ events include BG # of e- events include BG 3s CP sensitivity : |d|>20o for sin22q13=0.01 Nakaya

  22. CP sensitivity (3s) CHOOZ excluded sin22q13<0.12@Dm312~3x10-3eV2 stat+5%syst. stat+2%syst. (signal+BG) stat only stat+10%syst. no BG signal stat only JHF 3s discovery 3s CP sensitivity : |d|>20o for sin22q13>0.01 with 2% syst. Nakaya

  23. CERN SPL to Frejus 1023 x 2.2 GeV protons per year 4MW “Super-K” ~50 kT or “UNO” ~500 kT water Mezzetto

  24. Fluxes for SPL Beam Mezzetto

  25. d d Q13 Q13 Mezzetto

  26. Off-Axis CNGS to Gulf of Taranto CNGS neutrino fluxes (per proton) Flux (m-2) Without oscillations 1150 km nm 1200 km from CERN 1250 km ne En (GeV) Dydak

  27. Gulf of Taranto Detector p nm p nm p p nm n ~ 2MT fiducial mass running for 3 years with 5x1019 protons/year + ~ q Dydak

  28. Oscillation Amplitudes for 800 MeV Neutrinos nm - ne Earth Crust Oscillation Vacuum Oscillation Dm2= 0.001 eV2 Distance (km) Dm2= 0.0025 eV2 Dydak

  29. Off-Axis Numi Beams • ~ 2 GeV energy : • Below t threshold • Relatively high rates per proton, especially for antineutrinos • Matter effects to differentiate mass hierarchies • Baselines 700 – 1000 km Para

  30. Sources of the ne background ne/nm ~0.5% All K decays At low energies the dominant background is from m+e++ne+nm decay, hence • K production spectrum is not a major source of systematics • ne background directly related to the nmspectrum at the near detector Para

  31. NuMI Off-axis Detector Low Z imaging calorimeter: • Glass RPC or • Drift tubes or • Liquid or solid scintillator Electron ID efficiency ~ 40% while keeping NC background below intrinsic ne level Well known and understood detector technologies Primarily the engineering challenge of (cheaply) constructing a very massive detector How massive?? 50 kton detector, 5 years run => • 10% measurement if sin22q13 at the CHOOZ limit, or • 3s evidence if sin22q13 factor 10 below the CHOOZ limit (normal hierarchy, d=0), or • Factor 20 improvement of the limit Para

  32. A Modular Detector Built in Shipping Containers? Cooper

  33. Cooper

  34. Signal and background Fuzzy track = electron Clean track = muon (pion) Wojcicki

  35. Background examples nmCC - withp0 - muon NC -p0 - 2 tracks Wojcicki

  36. Two phase program? Phase I? (~ $100-200 M, running 2008 – 2014) • 50 kton (fiducial) detector with e~35-40% • 4x1020 protons per year (Nominal NuMI design plan… conservative? 6-8?) • 1.5 years neutrino (6000 nm CC, 70-80% ‘oscillated’) • 5 years antineutrino (6500 nm CC, 70-80% ‘oscillated’) Phase II? ( running 2014-2020) • 200 kton (fiducial) detector with e~35-40% • 20x1020 protons per year (needs new proton source) • 1.5 years neutrino (120000 nm CC, 70-80% ‘oscillated’) • 5 years antineutrino (130000 nm CC, 70-80% ‘oscillated’)

  37. NuMI Off-Axis Sensitivity for Phases I and II We take the Phase II to have 25 times higher POT x Detector mass Neutrino energy and detector distance remain the same Para

  38. Para

  39. Determination of mass hierarchy: complementarity of JHF and NuMI Combination of different baselines: NuMI + JHF extends the range of hierarchy discrimination to much lower mixing angles Minakata,Nunokawa, Parke Para

  40. BNL  Homestake Super Neutrino Beam Homestake BNL 2540 km 28 GeV protons, 1 MW beam power 500 kT Water Cherenkov detector 5e7 sec of running, Conventional Horn based beam Diwan

  41. AGS Target Power Upgrade to 1 MW  the AGS Upgrade to provide a source for the 1.0 MW Super Neutrino Beam will cost $265M FY03 (TEC) dollars Diwan

  42. 3-D Neutrino Super Beam Perspective Diwan

  43. UNO: The Study Baseline 500 kt Water Cerenkov 100 kT LANNDD ~Equivalent?

  44. Neutrino spectrum from AGS • Proton energy 28 GeV • 1 MW total power • ~1014 proton per pulse • Cycle 2.5 Hz • Pulse width 2.5 mu-s • Horn focused beam with graphite target • 5x10-5 n/m2/POT @ 1km Diwan

  45. Advantages of a Very Long Baseline  neutrino oscillations result from the factor sin2(Dm322L / 4E) modulating the n flux for each flavor (here nm disappearance)  the oscillation period is directly proportional to distance and inversely proportional to energy  with a very long baseline actual oscillations are seen in the data as a function of energy  the multiple-node structure of the very long baseline allows the Dm322 to be precisely measured by a wavelength rather than an amplitude (reducing systematic errors) Diwan

  46. MINOS 7.4 MINOS 25 VLB Application to Measurement of Dm322  the multiple node method of the VLB measurement is illustrated by comparing the BNL 5-year measurement precision with the present Kamiokande results and the projected MINOS 3-year measurement precision; all projected data include both statistical and systematic errors  there is no other plan, worldwide, to employ the VLB method (a combination of target power and geographical circumstances limit other potential competitors)  other planned experiments can’t achieve the VLB precision Diwan

  47. ne Appearance Measurements  a direct measurement of the appearance of nmneis important; the VLB method competes well with any proposed super beam concept  for values > 0.01, a measurement of sin22q13 can be made (the current experimental limit is 0.12)  for most of the possible range of sin22q13, a good measurement of q13and the CP-violation parameter dCP can be made by the VLB experimental method Diwan

  48. ne Appearance Measurements (Cont.) even if sin22q13 = 0, the current best-fit value of Dm212 = 7.3x10-5 induces a ne appearance signal  the size of the ne appearance signal above background depends on the value of Dm212; the figure left indicates the range of possible measured values for the ne yields above background for various assumptions of the final value of Dm212 Diwan

  49. Mass -ordering and CP-violation Parameter dCP  the CP-violation parameter dCP can be measured in the VLB exp. And is relatively insensitive to the value of sin22q13  the mass-ordering of the neutrinos is determined in the VLB exp; n1 < n2 < n3 is the natural order but n1 < n3 < n2 is still possible experimentally; VLB determines this, using the effects of matter on the higher-energy neutrinos Diwan

  50. Possible limits on sin22q13 versus dCP • For normal mass ordering • limit on sin22q13 will be 0.005 • for no CP • If reversed mass ordering • then need to run • antineutrinos Diwan

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