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NOnA and the US Neutrino Programme

NOnA and the US Neutrino Programme. Leslie Camilleri CERN, PH GDR Neutrino IPNO Orsay, 4 octobre 2006. Plan of Talk. Where do we stand and what do we still need to measure? NO n A

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NOnA and the US Neutrino Programme

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  1. NOnAand the US Neutrino Programme Leslie Camilleri CERN, PH GDR Neutrino IPNO Orsay, 4 octobre 2006

  2. Plan of Talk • Where do we stand and what do we still need to measure? • NOnA • The detector • Its performance • The NUMI beam • Its present and future performance • Its current user: MINOS. Present and expected performance. • NOnA sensitivity • NOnA status and schedule. • The US programme • Accelerators • Double b decay • Reactors

  3. 3-family oscillation matrix S = sine c = cosine • dCP violation phase. • q12drives SOLAR oscillations: sin2q12 = 0.314 +0.056-0.047(+- 16%) • q23drives ATMOSPHERIC oscillations: sin2q23= 0.44 +0.18-0.10 (+44% -22%) • q13the MISSING link ! sin2 q13< 0.03Set by a reactor experiment: CHOOZ.

  4. ne nm nt Mass hierarchySign of Dm223 Normal Hierarchy Inverted Hierarchy Dm122 = 7.9 x 10 -5 eV2 m3 m2 m1 > 0.05 eV2 Dm232= 2.7 x 10-3 eV2 Dm232= 2.7 x 10-3 eV2 m2 m1 Dm122 = 7.9 x 10 -5 eV2 m3 Oscillations only tell us about DIFFERENCES in masses Not the ABSOLUTE mass scale: Direct measurements or Double b decay Upper limit: Tritium b decay: mass (ne) < 2.2 eV Lower limit: (2.7 x 10-3)1/2> 0.05 eV

  5. What’s needed next? • Determine q13. • Determine the mass hierarchy. • Any CP violation in the neutrino sector?

  6. NOnA • 􀁺The NOνA Collaboration consists of 142 physicists and engineers from 28 institutions: • 􀁺Argonne, Athens, Caltech, College de France, Fermilab, Harvard, Indiana, ITEP, Michigan State, Minnesota-Twin Cities, Minnesota-Duluth, Northern Illinois, Ohio, Ohio State, Oxford, Rutherford, Rio de Janeiro, South Carolina, SMU, Stanford, Texas, Texas A&M, Tufts, UCLA, Virginia, Washington, William and Mary • 􀁺Five Italian universities with about 20 senior physicists are actively discussing joining NOνA. • Its main physics goal will be the study of νμ→νe oscillations at the atmospheric oscillation Dm2.

  7. Correlations in Oscillation Probability From M. Lindner: Measuring P (nm~ne) does NOT yield a UNIQUE value of q13. Because of correlations between q13, dCPand the mass hierarchy (sign of Dm231) CP violation: Difference between Neutrino and Antineutrino Oscillations Mass hierarchy accessible through Matter effects.

  8. Energy dependence of matter effects In vacuum and without CP violation: P(nm-ne)vac = sin2q23 sin2 2q13 sin2 Datm withDatm= 1.27 Dm232 (L/E) To be at maximum oscillation at L = 800km E must be 1.64 GeV, and at L = 295km E = 0.6 GeV Introducing matter effects, at the first oscillation maximum: P(nm-ne)mat = [1 +- (2E/ER)] P(nm-ne)vac withER = [12 GeV][Dm232/(2.7x10-3)][2.8 gm.cm-3/r]~ 12 GeV +-depends on the mass hierarchy. Matter effects grow with energy and therefore with distance. 3 times larger (27%) at NOnA (1.64 GeV) than at T2K (0.6 GeV)

  9. NOnA Detector Given relatively high energy of NUMI beam, decided to optimize NOnAfor resolution of the mass hierarchy. Go as high in energy as possible To keep L/E constant at 2.7 x 10-3 eV2 Go as far as possible, but remain in US. At Ash River near Canadian border (L = 810km) : New site. Above ground. Detector placed 14 mrad (12 km) Off-axis of the Fermilab NUMI beam (MINOS).

  10. Fully active detector consisting of alternating planes of horizontal and vertical 15.7m long plastic PVC tubes filled with liquid scintillator (BC 517L): Total mass 25ktons. Each tube viewed by a looped WLS fibre both ends of which are read by a single avalanche photodiode (APD). NOnA Detector 760 000 cells TiO2 Coated PVC tubes n Tubes are wide enough (6 cm) to allow large bending radius and no damage to fibre The loop is a “perfect” mirror

  11. Avalanche Photodiode Photon • Hamamatsu 32 APD arrays • Pixel size 1.8mm x 1.05mm (Fibre 0.8mm diameter) • Operating voltage 400 Volts • Gain 100 • Operating temperature: -15o C (reduces noise) Asic for APD’s: 2.5 pe noise

  12. Why APD’s ? The quantum efficiency of APD’s is much higher than a pm’s: ~80% . Especially at the higher wave lengths surviving after traversing the fibre.

  13. Fibre/Scintillator cosmic ray test Inserted looped 15.7m long fibre in 60 cm long PVC tube filled with liquid scintillator. Exposed to cosmic rays. 0 20 40 60 80 pe Measured 20 p.e. for a mip signal at the far end. Asic for APD’s: 2.5 pe noise  S/N ~ 8

  14. Half Block Prototype Being Builtat Argonne

  15. Location Surface detector with about 3m overburden to reduce the em component of cosmic rays.

  16. nm/nediscrimination ne CC nm CC Electrons shower: many hits/plane. Muons do not: just one hit/plane. nm CC background rejection: 7.1 x 10-4

  17. Neutral Current background: Npo Look like electrons and ne CC, if two photons are not recognized. nm NC background rejection: 1.3 x 10-3

  18. The MINOS/NOnA Neutrino beam: NUMI. Move horn and target to change energy of Beam

  19. Detector q Decay Pipe Target Horns OFF-AXIS Technique Most decay pions give similar neutrino energies at the detector: Neutrino Energy Spectrum is narrow know where to expect neappearance Can choose the off-axis angle and select the mean energy of the beam. ( Optimizes the oscillation probability)

  20. The Neutrino Beam components nm  nt Signal Sin22q13 = 0.04 Beam ne ~ 0.5% Major background Will have a NEAR detector to measure this ne spectrum

  21. MINOS detector Study of atmospheric mass region through nmdisappearance

  22. Far detector results Expected unoscillated Suppression of events at low energy

  23. New MINOS measurements K2K (Experiment ended) Compatible with and comparable to SK More precise than K2K.

  24. The MINOS future MINOS baseline 3.4 x 1020 pots / year Improvement by about a factor of 3 in 3 years

  25. The Proton Beam as of today 2.8 x 1013 p’s per spill (2.2 secs) ~280 kW For a Fermilab year of 2 x 107 secs 2.4 x 1020 pots/year. (Achieved 1.27 x1020in first turn-on year) MINOS baseline 3.4 x 1020 pots/year.

  26. The n beam after the collider shuts down (2009) • No antiproton production batches in Main Injector • No downtime for preparing collider shot. No time for antiproton transfer from accumulator to recycler. • Transfer time of 12 booster batches to Main Injector (0.8 sec). Instead transfer them to recycler during Main Injector cycle, and then transfer in one go • New RF in main injector • Upgrade of NUMI target. This should bring the Main Injector to a 1MW level Cost: 30-50 M$ . • PROTONS: 6.5 x 1020 protons on target per year. A gain of a factor of > 2 in numbers of protons delivered.

  27. Beam assumptions • 2010: Full shutdown to convert MI to 1 MW machine. • 2011: 44 weeks running at 400 to 700 kW (Partial (5kT)detector) • 2012: 38 weeks running at 700kW to 1 MW. • 2013 and beyond: 44 weeks at 1 MW. • Degradation factors assumed: • Accelerator uptime: 85%. • Average to peak intensity: 90%. • NOnA uptime: 90%. • Running time: • Start running as soon as 5kT installed. • 2 years to build up to full detector. • Run for 6 years from end of construction. Total: 60.3 x 1020 pots

  28. Signal and background I • 6% electron shower energy resolution • 3.5% muon energy resolution • Maximum likelihood applied to events to separate neevents from background. • Yields 23% efficiency for ne signal events including fiducial inefficiency • Background suppression: • 7.1E-4nm CC • 1.3E-3 Neutral Current • Optimized Figure of Merit • #Signal / sqrt(#bkd) = 32 • ~140 signal events for 60 x 1020 pot for sin2 2q13 = 0.1 • 19 background events. (12 intrinsic beam ne and 7 neutral currents)

  29. Signal and Background II • Statistical Power: why this is hard and we need protons 0.01 0.05 0.1 0.01 0.05 0.1 For sin2 213 = 0.1: : S=142.1, B=19.5 : S= 71.8, B=12.1

  30. 3 s sensitivity to q13 = 0 30.2 x 10 20 pot each n and n. (removes some correlation) n only 60.3 x 1020 pot The correlations are much reduced by running BOTH n and n. Discovery limit isbetter than 0.02for ALL d’sand BOTH mass hierarchies.

  31. Comparison to T2K and a Reactor Experiment T2K Reactor T2K may not be latest BraidwoodDouble Chooz Comparable to a Very sensitive reactor experiment Not very different

  32. 95% CL Resolution of the θ23 Ambiguity Combining accelerator experiments (sensitive to sin2(θ23)sin2(2θ13)) with reactor experiments (sensitive to sin2(2θ13))

  33. 95% CL Resolution of the Mass Ordering • Important to establish hierarchy: • Per se • If inverted next generation of double beta decay experiments can determine if the neutrino is its own antiparticle. • To measure CP violation need to remove hierarchy uncertainty because it contributes an apparent CP violation. Will depend on value of q13 !!

  34. Combining NOνA and T2K Δm2= 0.0030 eV2 Some improvement at high values of q13.

  35. δ vs. sin2(2θ13) Contours for Test points:Normal Mass ordering Normal Mass Ordering Some limited sensitivity at 1 s

  36. Cost and schedule • Total cost (Far and near detectors, building, admin etc…) 226 M$ (including 57 M$ contingency) Status • Approved by Fermilab Program Advisory Committee: Stage 1 Approval, (April 2005). • Prioritized by NuSAG. • Recommended by P5 for construction start in Fiscal Year 2008 (October 2007). • Critical Decision Zero (CD0) granted. Mission need. • Obtained CD1 approval: Range of Schedules and costs. • CD2 next end 2006(?): Final cost, schedule and TDR. • Granted $10M in R&D for generic oscillation experiment. • Proton Driver CD0 shelved at this stage. But R&D can continue. Alternative plans for Main Injector upgrade to 1 MW, maybe 1.2 MW. Schedule • Assumption: Approval early 2007. • Building ready: June 2009. (Agreement with U. of Minnesota). • Five kilotons: Early 2011. • Completion: 2012.

  37. The US programme: Accelerators I. • MINOS. • MiniBooNE nmne search • at the Fermilab booster: • Results on • the LSND observation this year. • High energy data already presented. • SciBooNE: K2K SciBar detector • In MiniBooNE beam: • low energy cross sections • MINERVA. n cross sections • at low energy in the • near hall of NUMI beam. • Going through approval • process

  38. The US programme: Accelerators II. • T2K 280m: Participation in 280m near detector supported. p0 detector inside the UA1/NOMAD magnet for the near detector and work on beam. • T2K 2Km: Participation in Water Cerenkov, civil engineering and liquid argon (150 tons). Only at later stage if possible. • Liquid argon R&D: to determine whether scalable to tens of kilotons.

  39. The US programme: Double –b decay. EXO:Potential for reducing the background by extracting and identifyng resulting Barium atom as a second stage NuSAG recommendations: Recommended the first three

  40. The US programme: Reactors. • NuSAG recommended a US experiment to get down to a sensitivity of sin2 2q13 of ~0.01. Both Daya Bay and Braidwood had this potential. • The DOE has stopped Braidwood and encouraged Daya Bay. • NuSAG encouraged participation in Double Chooz but with lower scientific priority because of its lower reach. • The DOE does not go along with this but possibly the NSF will.

  41. Very Long baseline: New NuSAG charge. • Assume a MW accelerator. • Discuss baselines: Compare 800km (NOnA), to 1300-2800km baselines: Fermilab or Brookhaven to new Underground site at Henderson or Homestake. • Types of detectors: Liquid Argon or Water Cerenkov? • Broad band: covering several oscillation maxima at once or narrow band. • Sensitivity and physics programme. • Joint BNL/FNAL study currently being carried out on these issues. Report: Oct. 2006

  42. Extra Slides

  43. Cost breakdown

  44. Far detector

  45. Near Detector in MINOS Surface Building 6.5 x 1020 pot in 75 mrad off-axis beam Kaon peak 45,000 nm CC events 2,200 ne CC events

  46. Confirmed by KAMLAND: Reactor antineutrinos to detector at Kamioka KAMLAND Solar Experiments KamLAND + Solar Completely consistent

  47. New MINOS measurements (Experiment ended)

  48. Why are neutrino masses so low???? Other particles Fascinating !!!!! Also Lower limit: (2.4 x 10-3)1/2> 0.05 eV

  49. APD response Measured with light equivalent to one and two mip’s Noise Signal well separated from noise 0 20 40 60 80 pe

  50. Summary of backgrounds Efficiency for ne signal: 24%

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