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Summary of  13 Measurements and Prospects

AAP 2012 meeting, Honolulu Jelena Maricic University of Hawaii October 4, 2012. Summary of  13 Measurements and Prospects. Executive Summary.  13. Summary of  13 measurements from reactors 2011-2012. Daya Bay  13 ~8.7 (~8  zero exclusion) RENO

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Summary of  13 Measurements and Prospects

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  1. AAP 2012 meeting, Honolulu Jelena Maricic University of Hawaii October 4, 2012 Summary of 13Measurements and Prospects

  2. Executive Summary 13

  3. Summary of 13 measurementsfrom reactors 2011-2012 • Daya Bay • 13 ~8.7 (~8  zero exclusion) • RENO • 13 ~9.8 (~6  zero exclusion) • Double Chooz • 13 ~9.6 (~3  zero exclusion)

  4. Summary of 13 measurements from beams • MINOS T2K ~3  zero exclusion 13 ~9 (NH) 13 ~10 (IH) 13 ~7 (NH) 13 ~9 (IH) ~2  zero exclusion

  5. Summary of 13 measurements • Global fit from Daya Bay, RENO, Double Chooz and T2K: 4 Sin213 = 0.0241 ± 0.0025 (NH) Sin213 = 0.0244 ± 0.0025 (IH) 3 N 2 13 = 8.9± 0.9 1 (~10% relative uncertainty) Fogli, Lisi, Marrone, Montanino, Palazzo, Rotunno: hep-ph/1205.5254 (2012)

  6. Prospects • 13 measured to be non zero with > 7 C.L. • In the next 3 years expected to be known with 5% uncertainty • Going from the unknown to the best measured neutrino mixing angle: 2003-2012 But there is more to this measurement…

  7. 13 Outline • Introduction • Review of the experiments • Results of measurement 13 • Prospects Material adopted from presentations from NOW2012 and ISNP 2012, from members of MINOS, T2K, Double Chooz, Daya Bay and RENO

  8. Introduction 13

  9. Starting point in 2003: CHOOZ CHOOZ experiment R = 1.01  2.8%(stat)2.7%(syst) Last non-measured neutrino mixing angle! Only the upper limit on the value of angle θ13 wasset! CHOOZ experiment constraint: (e  e disappearance exp) @m2atm = 2.3 10-3 eV2 sin2(2θ13) < 0.15 (90% C.L) e  x M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374 M. Apollonio et. al., Eur.Phys.J. C27 (2003) 331-374 13 < 11

  10. 13 central to fundamental questions • CP-violation phase and mass hierarchy Δm221=(7.50+0.19-0.20)×10-5 eV2 (KamLAND) Δm232=(2.32+0.12-0.08)×10-3 eV2 (MINOS) “Solar” 12 ~ 30° “Little mixing angle” 13 < 11° (circa 2011) (CHOOZ) “Atmospheric” 23 ~ 45° (SK + MINOS) • 13 impacts measurements on ~few 100 m scale and above • Interesting for nuclear reactor monitoring with neutrinos Value of θ13directly influences prospects of measuring CP violation phase in the weak sector!

  11. Hints on 13 from global fits in 2005/2008 sin2 13 = 0.016 ± 0.010 Fogli, Lisi, Marrone, Palazzo, Rotunno: hep-ph/0806.2649v2 (2008) 13 ~ 7 sin213 = 0.9+2.3−0.9 × 10−2 13 ~ 5 Large uncertainty and low non-zero exclusion level. Fogli, Lisi, Marrone, Palazzo: hep-ph/0506083 (2005)

  12. Global fit from KamLAND in March 2011 sin2 13 = 0.020 ± 0.016 KamLAND collaboration: hep-ex/1009.4771 13 ~ 8 Large uncertainty and low non-zero exclusion level.

  13. Review of 13 experiments 13

  14. 13 Measurement Strategies • Use muon neutrinos from accelerator: appearance search for electron neutrinos • MINOS • T2K • Use electron antineutrinos from nuclear reactor: disappearance search • CHOOZ • Double Chooz • Daya Bay • RENO

  15. 13 and Beam Experiments MINOS e • T2K uses off-axis beams to achieve: • Increased flux near oscillation max • Reduced high energy NC bkg µ e T2K µ

  16. 13 and Reactor Experiments Near Detector Far Detector Reactor e e (Flux)L2 No Oscillations Eν ~ 4 MeV < 14% Oscillated ~1.5km L High precision measurement required: systematic error ~0.5%

  17. 13& Reactor Experiments • <E> ~ a few MeV only disappearance experiments sin2(213) measurement independent of -CP • P(e e) = 1 - sin2(213)sin2(m231L/4E) + O(m221/m231) •  weak dependence in m221 • a few MeV e + short baselines  negligible matter effects (O[10-4] ) •  sin2(213) measurement independent of sign(m213) 13 & BeamExperiments Appearance probability :  dependences in sin(213), sin(23), sign(m231), -CP phase in [0,2]

  18. Results of measurement 13 with beams 13

  19. 735 km MINOS Experiment MINOS - Main Injector Neutrino Oscillation Search Two functionally identical detectors to reduce systematics Near Detector • 1 km from target • 94 m underground, 225 mwe • Measures the energy spectrum and beam composition Far Detector • 735 km from target • 700 m underground, 2070 mwe • Re-measures the neutrino beam composition nm Near Detector 980 tons Far Detector 5,400 tons

  20. 2.54 cm Fe Extruded PS scint. 4.1 x 1 cm WLS fiber U V planes +/- 450 Clear Fiber cables Multi-anode PMT Detector Technology • Steel/scintillator tracking calorimeters • Alternate orthogonal orientation planes • Steel absorber 2.54 cm thick • Scintillator strips 4.1 cm wide, 1.0 cm thick • 1 GeVmuons penetrate 28 layers • Longitudinal sampling = 1.4 radiation lengths • Optical WLS fiberreadout to multi-anode PMTs Magnetized • <B> = 1.3T • Muonenergy from range/curvature • Distinguish μ+fromμ- tracks

  21. n e- m- Neutrino Interactions in Detectors transverse direction nm Charged Current nx Neutral Current ne Charged Current long μ track & possible hadronicactivity at vertex short with diffuse shower short with compact EM shower profile beam direction color scale represents energy deposition

  22. Neutrino Mode Monte Carlo Neutrino mode Horns focus π+,K+ Decay Pipe Focusing Horns Target 2 m π- νμ 120 GeV protons νμ π+ 30 m 15 m 675 m

  23. Antineutrino Mode Monte Carlo Monte Carlo Antineutrino mode Horns focus π-,K- Neutrino mode Horns focus π+,K+ Decay Pipe Focusing Horns Target 2 m π+ νμ 120 GeV protons νμ π- 30 m 15 m 675 m

  24. νeAppearance Measurement In matter, νeCC scattering modifies oscillation probability ~30% in MINOS sensitive to neutrino mixing angle θ13, δCP, mass ordering

  25. Electron Appearance in FHC and RHC Beam ν mode Expected (LEM>0.7): 69.1 (background, if θ13=0) 26.0 (signal, if sin2(2θ13)=0.1) Observe: 88 events ͞νmode Expected (LEM>0.7): 10.5 (background , if θ13=0) 3.1 (signal, if sin2(2θ13)=0.1) Observe: 12 events 10.6×1020 POT (ν mode) 3.3×1020 (͞νmode) • Library Event Matching (LEM)

  26. ne Appearance:ν and  CombinedContour

  27. T2K experiment Tokai Kamioka KEK J-PARC in JAEA J-PARC in JAEA Tokyo Super-Kamiokande J-PARC Second generation long-baseline neutrino-oscillation experiment; ● from Tokai toKamioka High intensity almost pure nm beam from Main Ring in J-PARC is shot toward the Super-Kamiokande detector 295km away. ● ● The physics data-taking started in Jan. 2010, and stopped in March 2011 by the earthquake. Resumed almost a year later. ●

  28. Results of measurement 13 with reactors 13

  29. Locations Double Chooz Daya Bay RENO

  30. Double Chooz Configurations 115 mwe 300 mwe 400 m 1 km Daya Bay

  31. Reactor Neutrino Detection Signature • Reactors as neutrino sources: Chooz: P =2x4.25GWthN~2x1021s-1 Neutrino detection via inverse  decay Target: Gd doped scintillator 1 g/l Gd in LS Distinctive two-step signature: -prompt event Photons from e+ annihilation Ee = E-0.8 MeV + O(Ee/mn) -delayed event Photons from n capture on dedicated nuclei (Gd) t ~ 30 s E ~ 8 MeV Gadolinium

  32. The Double Chooz Far Detector Calibration Glove Box Outer Veto (OV)plastic scintillator strips Outer Steel Shielding250 t steel (15 cm) Inner Veto (IV)90 m3 of scintillator in a steel vessel (10 mm) equipped with 78 PMTs (8 inches) Buffer110 m3 of mineral oil in a steel vessel (3 mm) equipped with 390 PMTs (10 inches) γ-Catcher (GC)22.3 m3 scintillator in an acrylic vessel (12 mm) Target10.3 m3 scintillator doped with 1g/l of Gd compound in an acrylic vessel (8 mm) ~7m

  33. Daya Bay

  34. 13 Measurement with DC Far 13

  35. Interaction Cross-Section • Recalculations of spectra introduced normalization shift; “anomaly”? • Th.A. Mueller et al, Phys.Rev. C83(2011) 054615. • P. Huber, Phys.Rev. C84 (2011) 024617

  36. Reference Spectra + Bugey4 “Anchor” Normalize to Total Rate Measurement of Bugey4 Reduces reactor normalization uncertainty from 2.70% to 1.76%

  37. Neutrino Candidate Selection Prompt signal Evis = [0.7, 12.2] MeV Delayed signal Evis = [6.0, 12.0] MeV Delayed Coincidence Δt = [2, 100] µsec Require Δt μ > 1 msec PMT light noise rejection cuts PMT hits approx. homogeneous PMT hits approx. coincident in time Multiplicity conditions: No extra events around signal Background rejection: No coincident signal in OV Require Δt μ > 500 msec if Eμ > 600 MeV • Plus three irreducible backgrounds: • Accidentals • Cosmogenic 9Li • Fast neutrons/stopping muons

  38. Neutrino Candidate Selection Prompt signal Evis = [0.7, 12.2] MeV Delayed signal Evis = [6.0, 12.0] MeV Delayed Coincidence Δt = [2, 100] µsec Require Δt μ > 1 msec PMT light noise rejection cuts PMT hits approx. homogeneous PMT hits approx. coincident in time Multiplicity conditions: No extra events around signal Background rejection: No coincident signal in OV Require Δt μ > 500 msec if Eμ > 600 MeV Minimum visible energy of ν signal Prompt energy cut Preliminary Trigger efficiency • Threshold at 400keV (ε=50%) • ε=100% above 700keV

  39. Neutrino Candidate Selection Prompt signal Evis = [0.7, 12.2] MeV Delayed signal Evis = [6.0, 12.0] MeV Delayed Coincidence Δt = [2, 100] µsec Require Δt μ > 1 msec PMT light noise rejection cuts PMT hits approx. homogeneous PMT hits approx. coincident in time Multiplicity conditions: No extra events around signal Background rejection: No coincident signal in OV Require Δt μ > 500 msec if Eμ > 600 MeV

  40. Neutrino Candidate Selection Prompt signal Evis = [0.7, 12.2] MeV Delayed signal Evis = [6.0, 12.0] MeV Delayed Coincidence Δt = [2, 100] µsec Require Δt μ > 1 msec PMT light noise rejection cuts PMT hits approx. homogeneous PMT hits approx. coincident in time Multiplicity conditions: No extra events around signal Background rejection: No coincident signal in OV Require Δt μ > 500 msec if Eμ > 600 MeV

  41. Neutrino Candidate Selection Prompt signal Evis = [0.7, 12.2] MeV Delayed signal Evis = [6.0, 12.0] MeV Delayed Coincidence Δt = [2, 100] µsec Require Δt μ > 1 msec PMT light noise rejection cuts PMT hits approx. homogeneous PMT hits approx. coincident in time Multiplicity conditions: No extra events around signal Background rejection: No coincident signal in OV Require Δt μ > 500 msec if Eμ > 600 MeV

  42. Neutrino Candidate Selection Prompt signal Evis = [0.7, 12.2] MeV Delayed signal Evis = [6.0, 12.0] MeV Delayed Coincidence Δt = [2, 100] µsec Require Δt μ > 1 msec PMT light noise rejection cuts PMT hits approx. homogeneous PMT hits approx. coincident in time Multiplicity conditions: No extra events around signal Background rejection: No coincident signal in OV Require Δt μ > 500 msec if Eμ > 600 MeV • 41% of 9Li BG is rejected by additional muon veto (~5% live-time loss) • 28% of fast neutron/stop μ BG is rejected by OV anticoincidence

  43. Candidate Rate Variation • Before 9Li reduction cut, no OV anticoincidence applied • Not background-subtracted • Rate consistent with expectation

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