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Future Neutrino Oscillation Experiments

Future Neutrino Oscillation Experiments. Ed Blucher. Neutrino oscillations, CP violation, and importance of  13 Accelerator vs. reactor experiments Future reactor experiments to measure sin 2 2 13. Neutrino Oscillations.

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Future Neutrino Oscillation Experiments

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  1. Future Neutrino Oscillation Experiments Ed Blucher • Neutrino oscillations, CP violation, and importance of 13 • Accelerator vs. reactor experiments • Future reactor experiments to measure sin2213 EFI Faculty Lunch

  2. Neutrino Oscillations During last few years, oscillations among different flavors of neutrinos have been established; physics beyond the S.M. Mass eigenstates and flavor eigenstates are not the same (similar to quarks): mass eigenstates flavor eigenstates MNSP matrix • Raises many interesting questions including possibility of CP violation in neutrino oscillations. • CP violation in neutrino sector could be responsible for the matter-antimatter asymmetry.

  3. Quark and Neutrino Mixing Matrices

  4. 2 Flavor Neutrino Mixing The time evolution of the flavor states is: For a beam that is pure  at t=0,

  5. MNSP Matrix 12 ~ 30° sin2 213 < 0.2 at 90% CL 23 ~ 45° What is e component of 3 mass eigenstate?

  6. CP Violation in Neutrino Oscillations Minakata and Nunokawa, hep-ph/0108085

  7. Methods to measure sin2213 • Appearance nmne(Accelerator Exp) • Use fairly pure, accelerator produced nm beam with a detector at long distance (300 km - 900 km) from the source • Look for the appearance of ne events • Use near detector to measure background nes (beam and misid) 150m 1500m • Disappearance(Reactor Exp) • Use a set of reactors as a source of • ne's with a detector at few km • Look for a non- 1/r2 behavior of the ne rate • Use near detector to measure the unoscillated flux Diablo Canyon, CA overburden

  8. Accelerator and reactor measurements of 13 Accelerator experiments measure: Reactor measurement of 13 is independent of matter effects and CP violation:

  9. Reactor Measurements of Neutrino Oscillations Reactors are copious sources of per second. Detection of antineutrino by followed by or for Gd-loaded scintillator

  10. Long history of neutrino experiments at reactors 20 m KamLAND 6 m CHOOZ Current interest is focused mainly on possibility of measuring 

  11. Reactor Measurements of Future: Search for small oscillations at 1-2 km distance (corresponding to Pee Reactor experiments allow direct measurement of sin22: no matter effects, no CP violation, almost no correlation with other parameters. Sensitivity goal: sin22~0.01. Level at which long-baseline “superbeams” can be used to measure mass hierarchy, CPV; ~ sensitivity goal of proposed accel. expts. Distance to reactor (m)

  12. Previous Reactor  Experiments CHOOZ Systematic Errors • CHOOZ and Palo Verde Experiments • Single detector experiments • Detectors used liquid scintillator with gadolinium and buffer zones for background reduction • Shielding: • CHOOZ: 300 mwe • Palo Verde: 32 mwe • Fiducial mass: • CHOOZ: 5 tons @ 1km, 5.7 GW • ~2.2 evts/day/ton with 0.2-0.4 bkg evts/day/ton • ~3600 n events • Palo Verde: 12 tons @ 0.85km, 11.6 GW • ~7 evts/day/ton with2.0 bkg evts/day/ton • ~26000 n events

  13. CHOOZ Target: 5 ton Gd-doped scintillator

  14. Is it possible to improve the Chooz experiment by order of magnitude (i.e., sensitive to sin22 ~ 0.01)? Add second detector; bigger detectors; better control of systematics. ~200 m ~1500 m • What systematic error is attainable? • Efficiency and energy calibration strategy (movable detectors?) • Backgrounds • Multiple reactor cores • Site / depth • Choice of scintillator (stability of Gd-loaded scintillator) • Size, distance of detectors

  15. Normalization and spectral information Predicted spectrum 13=0 Observed spectrum sin2213=0.04 • Counting Experiment • Compare number of events in near and far detector • Energy Shape Experiment • Compare energy spectrum in near and far detector E (MeV) E (MeV)

  16. Counting exp. region Spectrum & Rate region (12 ton det.) (250 ton det.) Analysis Using Counting and Energy Spectrum(Huber et al. hep-ph/0303232) scal relative near/far energy calibrationsnorm relative near/far normalization 90%CL at Dm2 = 3×10-3 eV2 Scenarios:Reactor I = 12ton×7GW×5yrsReactor II = 250ton×7GW×5yrs

  17. Worldwide interest in two-detector reactor experiment Workshops: Alabama, June 2003 Munich, October 2003 Niigata, Japan, March 2004 Based on early workshops, a whitepaper describing physics possibilities of reactor experiment has been written.

  18. Sites under discussion: • Kraznoyarsk (Russia) • Chooz (France) • Kashiwazaki (Japan) • Diablo Canyon (California) • Braidwood, Byron (Illinois) • Wolf Creek (Kansas) • Brazil • Taiwan • China

  19. ~20000 ev/year ~1.5 x 106 ev/year Kr2Det: Reactor 13 Experiment at Krasnoyarsk Features - underground reactor - existing infrastructure Detector locations constrained by existing infrastructure Reactor Ref: Marteyamov et al, hep-ex/0211070

  20. Proposal for Reactor 13 Experiment in Japan Kashiwazaki-7 nuclear power stations; world’s most powerful reactors - requires construction of underground shaft for detectors far near near Kashiwazaki-Kariwa Nuclear Power Station

  21. Kashiwazaki:Proposal for Reactor 13 Experiment in Japan far near near 70 m 70 m 200-300 m 6 m shaft, 200-300 m depth

  22. The Chooz site, Ardennes, France … Double-CH1313Z …

  23. The Chooz site ? Near site: D~100-200 m [severall options under study] Far site: D~1.1 km, overburden 300 mwe [former experimental hall] • Positive signs from EDF for reusing the former CHOOZ site. Near site  civil engineering • 2x11.5 tons, D1=100-200m, D2=1050m. Sensitivity: 3 years  sin2(213) < ~0.03 • Chooz, 2x10 tonnes, D1=0.7 km, D2=1.1 km, 3 ans (70 kevts)  sin2(213)<0.037

  24. CHOOZ-Far

  25. CHOOZ-Far detector 3.5 m Existing CHOOZ tub 7 m

  26. CHOOZ-Near new Laboratory ~10-15 m High-Z material ~5- 15 m

  27. U.S. Nuclear Power Plants

  28. Braidwood, Illinois 7.17 GW 24 miles SW of Joliet

  29. Braidwood site

  30. 2 underground  detectors Diablo Canyon Nuclear Power Plant 1500 ft • Powerful: Two reactors (3.1+ 3.1 GW Eth) • Overburden: Horizontal tunnel could give 800 mwe shielding • Infrastructure: Construction roads. Controlled access. Close to wineries.

  31. We’ve formed a small collaboration to develop a proposal for a • midwest site: • Chicago, Columbia, ANL, FNAL, Kansas, Michigan, Oxford, Texas Chicago involvement: Kelby Anderson, Ed Blucher, Juan Collar, Jim Pilcher, Matt Worcester (postdoc), Erin Abouzaid (grad), Abby Kaboth (undergrad), Jennifer Seger (undergrad) • Significant effort also underway at LBNL to investigate feasibility • of experiment at Diablo Canyon.

  32. Conclusions • Extremely exciting time for neutrino physics! • The possibility of observing CP violation in the neutrino sector presents a great experimental challenge. • Reactor and accelerator experiments are complementary. • Reactor experiment has potential to be faster, cheaper, and better for establishing value of .

  33. Was baryogenesis made possible by leptonic CP violation? Leptogenesis may have been the result of direct CP violation in decays of heavy Majorana particles: This antilepton excess in converted to a baryon excess through nonperturbative Standard Model B-L conserving processes. - Fukugita and Yanagida, Phys. Lett. B174 (1986)

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